George_Jetson

Glad to hear it worked out well. You will know for sure after a few engine cycles. Do not be concerned about the light remaining on immediately after you replace it. The check engine light will remain on until the computer has verified that the sensor is working correctly. In the case of a A/F sensor, this includes waiting until the engine and the sensor has reached temp.

Keep in mind that if the throttle is sticking, most of the problem will be with the throttle shaft where it goes thru the throttle body. The deposites that you see in the throttle bore cause problems, but sticking is not the main one.

That does not sound right. Try running diagnostics on the HVAC system. To enter diagnositcs, with the ignition off. Press and hold the AUTO button and REC/FRESH button, and while holding the buttons, turn on the ignition. See if there are any codes displayed. Since the outside temp is displaying correctly, I would suspect that the inside temp sensor is open or shorted.

Ok, since the resistance of the valve is too high, and it is not switching I would say replace the valve. I would suggest that when you pick up the valve, that you also see if they have the egr sensor. If you bring your meter with you, you can compare the readings with what the sensor on your car is reading. At this point I would NOT purchase a sensor. The fact that the valve is not switching is enough to explain why you are getting the code.

Ok Alldata indicates that the coil should read about 33 to 39 ohms, assuming they are right, you have a problem. The black thing on the right hand side of the valve is a filter. According to alldata with no power applied to the valve you should be able to blow air from the center port (the one pointing up in you picture) to the port and the left hand side. Then if you apply 12 volts across the terminals, you should be able to blow air from the center port, to the filter on the right hand side. There are two things that concern me. 1) you read the wrong resistance on the egr temp sensor, this is confusing since the voltage readings that you are getting are app what I would expect. So with this in mind, I would note this, but take no action at this point. Focus your attention on the valve. 2) you are reading a much higher resistance on the valve than what the spec calls out. If you have access to a air compressor with a regulator you can set the reg to 10 to 15 psi. Rig up fittings so that you can apply the pressure to the center fitting and see what happens. You want to be able to apply 12 volts and see if the valve switches. If it does switch, see if you can get it to reliably while switching it fairly rapidly. I recomend testing the valve, with a compressor, my guess is that you will probably find the problem here. I work with this type of computer controlled valves every day, it is very possible that the valve is sticking and causing this problem. From the schematics, it appears that it is used in a pulse width modulated circuit and sticking would explain the problems you are having. The fact that some of the other data is contadicting is making this a little more difficult, but the test on the valve will tell us a lot.

SO, I pulled a vacuum on the hose that goes to the top of the EGR Valve and sure enough the engine idles very rough and almost dies then goes back to good idle when I let loose the vacuum. EGR must be ok. This indicates that the erg valve is good. I then red the voltage accross the EGR Gas Temperature sensor and at idle it is about 3.9 volts then as I increase the RPM it drops below 2 volts in about 30 seconds. It may be ok. I also read NO ohms accross it. Being a sensor there maybe should not be. This appears to be a contradiction, the changing voltage does not agree with NO ohms. I believe that it should read app 2.5 k ohms when cold, and less when hot. Does your DVM have a auto range, or manual range? My guess is that it was on the wrong range. I then check the Vacuume switching Valve (see photo) I get 1k ohms accross the leads on way then switch the leads and I get an open curcuit. I can not draw vacuum on either hose fittings weather I put voltage on it or not, I get air through it at both fittings, both ways. I will need to look up the actual vac ports on the valve, this may be the problem. I am at work right now and do not have access to my manuals This may be the problem. Your turn!!.....just kidding. phil

It's good to hear that you have it fixed. I think auto manufactures really should re-design the idle stop screw. Many people do not realize that on a fuel injected car, it should not be touched, period. It will always be something else that is causing the problem (except when it has already been messed with, and you are just trying to return it to the original position). Even in the days of carb engines, the throttle screw has limited adj range. If you adj it too far you will mess up the idle transition circuit of the carb, and it would stumble off idle.

spongy brakes are normally caused by air in the brake system. If there is air inside the ABS unit, it can be difficult to remove without as bi-directional scanner (the valves inside the abs must open to bleed it properly). Take it back and have them correct the problem.

I would not be concerned at all about carfax not showing maint records. I also used to work as a mechainc, and still keep all of my ASE certs current. Personally I believe the only things of significance on carfax will be neg. A experience eye can tell if there has been routine maint on a car.

Compression check seems easy to do. I'll try to look for the tester, or pay a visit to a dealer. I don't know how much, but I post it here? How much in US? Us you can pick up a gauge from $45 for a decent unit, professional units are more expensive. Plugs are dry, a little dark, I should've taken some pics of it. That's good, is there any signficant difference between the 6 of them? IE is one much lighter, or darker? I see that you have an experience. Really, would you say that adjusting spark plug gap is OK? Checking the gap is not optional, you must do it, trust me on this one. Some engines are more sensitive to gap than others. I have a new NGK BKR6EP-11 here, waiting for replace, bought them sooner - was a good price on them. I measured the gaps with a slide calliper (0,02mm tolerance), they are perfectly OK. It has 235000km (around 142000miles). Changed oil, oil filter, ATF (filter last year - wasn't required), coolant, brake fluid, maybe soon I'll drain the powersteering/cooling fan fluid (Dexron II). I'll measure the resistance of spark plug wires, do a compression check. I will change the plugs in march. How to check cap and rotor? Btw, aren't those supposed to be in a carburated engine? I would suggest buying a replacement cap and rotor. That way you will have something to compare it to. If you do not need it, you can always return it if it has not been installed. The wear will be evident, especially if you have the the new one to look at. And carburated engines have no bearing on if it has a dist or not. Later model lexus (ie 94 up) do not have dist Tranny was drained and filled twice this year, it was brown, now its more orange (cca 6 litres in tranny + cca 3 litres in reservoir) Just plz tell me, when adjusting throttle cable (kick-down tranny cable), manual says that there should be a 0-1mm of stopper visible from a rubber boot. But after adjustment, there is still a little slack. And when engine started and fully warmed up, the dashpot moves down resulting in -1mm inside the rubber boot (outside cable) with bigger slack. What about this? that I would have to look up, cannot do that at this moment.

The plugs should be a very light tan and dry. Black is a indication of too rich, wet is even worse. Most auto part stores carry compression testers. It is a simple procedure. I don't know how much dealers charge per hour over there, but in the states you can buy a very good compression checker for less than 1 hours labor. The procedure is simple, first make sure that the battery is full charged and remove the fuel pump relay. Next remove all spark plugs, note the condition of each plug ie color, and is it dry or wet. The compression tester will have a gauge, with a hose with a fitting that screws into the spark plug hole. You screw the compression tester into one cylinder and then crank the engine for several seconds (with the throttle held open). The gauge will read, and hold the peak pressure. Note the peak pressure, and then move the gauge to the next cylinder, and repeat the process. The compression should be about 180 psi, but the difference between the highest and lowest reading is the most important thing here. 5% is good ie 15~20 psi. The greater the difference the worse the problem.. This is also a good time for a tune up. You state the plugs are ok? How many miles/kilometers? Were the gaps checked? Very important! I used to not believe that gapping plugs was critical, I do believe it now ( I have several ASE certs, one is the L1 advanced engine diagnostics, I have a little bit experience with this). I assume that you have also measured the resistance of the spark plug wires, along with checking the cap and rotor. Once you check the compression, let us know what the results are. Now as far as auto transmission go, they are not my strong point. I do know the basics, and I assure you that you will be in a much better position to evaluate the trans after you have figured out why the engine is running poorly. At this point I would just make note of the transmission fluid condition, and make sure that the level is correct.

95 does not measure egr pressure, Although I will commend you for taking the initive to research the problem instead of jumping right in with the questions, the approach to troubleshoot this must be different. What the issue you are having is that although the code is the same, the method that they detect the condition is totally different. This year uses a temp sensitive resistor to measure the presence of EGR, with no egr flowing it expects to see low temps. The code is for excessive flow, so it thinks there is egr when it is not called for. If you have a hand held vac pump, you could apply vac to the egr and see if it moves freely, and then returns to the closed position when vac is removed. Next start the engine and let it idle ( I assume that idle quality is good ). With the engine at idle, apply vac to the egr valve. It should stumble and run VERY rough, if not die alltogether. With these tests you have elimated the egr valve (or condemed it). If you do not have a hand held pump, I would recomend buying one, it will come in very useful for many different things. Harbor Freight sells a cheapie that will work ok for a average person. It run around $10 The next step I would recomend checking the temp sensor Measure the resistance, I believe that it should be around 2.5 k ohms when cold. Try these things, and then let us know what you have found, chances are you will have found the problem with these tests, if not, I can tell you how to the the other components in the system.

TPS can cause all sorts of problems with accelerating, but without the throttle moving, the voltage should be steady. The MAF should also be fairly steady. I would suggest checking compression, note the color of each plug, and any issues with compression. You should be seeing around 180 psi (not sure what that would translate to kg cm3). If there are any low cylinders pay special attention to the condition of the plug. Do not worry about the transmission now, focus your attention into getting the engine running correctly. Do not get overwhelmed by the list of possible causes, you need to check the basics, chances are that you will find the clue that will point to what should be checked next. I think that you are mistaken on how much these engines can adapt, there is a small window of adj, but once it gets out of that window you will notice problems.

95 does not have a egr position valve. The original post is for 97, which does have a position sensor.

I suggest removing the throttle body and soaking it, you really need to get it move freely. Next I would suggest checking the coolant temp sensor, keep in mind that the computer uses it's own separate sensor. So just because the dash gauge reads normally, the computer sensor could still be bad. A bad sensor could explain the rich mixture. The next thing to check are the O2 sensors Bank 1 sensor 1 & bank 2 sensor 1. These control the mixture and could also explain the rich condition. I do not think that the MAF is your problem, but it is a good idea to check it thoughtly. Keeping in mind that the sensor is mainly a mechanical device on this year. First make sure the vane moves freely, without sticking. Measure the voltage, +5, grd and signal. The signal should change smothly if you move the vane with your finger. And measure the Air temp sensor (inside the MAF)) Have you done a compression check? And what is the mileage on your car?

Try taking the cables off of the throttle body, see if the thottle blade moves smoothly then. You need to isolate what is actually binding. You may have to pull the entire body off to soak it in cleaner, but you must get it to move freely. As for the IAC, did you spray it with cleaner, or did you take it apart? If may need to be taken apart, but concentrate on the throttle body first Until that is moving correctly, you will not get good throttle control even if the IAC is working correctly. You did not mention in your post, but have you checked all the vac hoses? Including the PCV? Leaks of un metered air will also cause problems with unstable idle. The picture in you first post, the arrow is pointing around 750 RPM, that is normal. Are you saying at that speed it is shaking the steering wheel? If so check the plugs/wires/dist cap. What color are the plugs? Can you smell gas in the exhaust? How many miles on the car? Last the hard shifting, are you talking about between gears? Or just when you move between drive/ neut/ rev?

You should not have adj the throttle stop screw. If possible, try to return it to the original position. It sounds like you have a couple problems. First, the sticking throttle, Remove the rubber intake tube, and check the throttle blade. It probably has a buildup of dirt around the blade and body. This is restricting the normal airflow into the engine. Get a can of carb cleaner, use a couple rags, and clean off all the dirt. Second, there is a air idle control valve. This valve is probably dirty, and sticking. This valve is what the ECM uses to control idle speed. Do a search on this forum, there is a lot of information on the idle control, and how to clean it.

When you turn the key to the start position, all you hear is a whine, no clicking noise? Open the hood and while a friend turns the key to start, stand beside (not in front) of the car. Put your hand on the starter, what do you hear/feel. Does it appear that the starter is turning, but not engaging? That would mean either a problem with the solenoid, or the overrun clutch on the starter. Either way, the next step is to pull the starter. Check the teeth on the flex plate, and then purchase a rebuild.

You are not very clear on your description. Does it sound like the engine is turning over? Can you hear the starter engage, does the starter sound like it is turning over?

A leak could cause lean mis-fires, which is why I was asking about how it ran above idle. The coil packs are all tied to the same 12 volt source, the ignitor grnds the individual coils. Of course you can extrapolate that there is at least one splice for the wire that supplies power to the coils, and you can check it (should have 12v all the time the engine is on). If the engine runs reasonable above idle, then I would strongly supect leaks. Bring some assorted sizes of vac lines and some tape (in case the flex tube is leaking). As far as tune-ups, I always recomend doing one if there is a driveability issue, and if it has been awhile. I used to work at a dealership, you would not believe how many cars came in with complaints, cel, yet had not had a tuneup in a long time. Part of this I attribute to the auto manufactures themselves, I believe that the advertisments that their cars can go 100k without a tuneup is BS. Missfires can damage cats due to unburned fuel burning inside the cat. There are also other issues, but suffice to say, if they really thought they could make it to 100k, why doesn't the warrenty extend that far?

No, variable valve timming is for later engines. You state that it runs rough at idle, how does it drive otherwise? The first thing I would suggest it to check vac hoses. CLOSELY, hoses over time will dry and crack, especially at the ends. Don't forget to check the PCV valve hose, it is a little hard to see unless you are intentionally looking for it, very easy to overlook. How long since the last tuneup?

I looked up the code P0402, and it is for excessive egr flow. There are several things that can cause this, such as a stuck egr valve, stuck vsv valve, short in the vsv valve ciruit, or lastly a problem with the egr temp sensor. How does the car idle? I would assume that the egr valve is closing because if it was stuck open at idle, the idle would be so rough that you would have mentioned that. So I would suggest starting with the last item. The egr temp sensor. There is a thermistor located on the egr tube, when egr flows this thermistor is heated up. When the senor is hot, the resistance is low, and the ECM reads this resistance to verify that the egr is flowing. So if you have a DVM, wait or the engine to cool, and measure the resistance of the sensor. According to Alldata, it should be around 2.5k ohms when cold. If it reads significantly less than you have found the problem. I would recomend taking the dvm to the auto parts store to verify the resistance of the new sensor before you buy it. Just in case my manual is wrong. Generally a auto part store will not allow you to return a electrical item, but I have yet seen one that will not let you measure the resistance when you are standing at the counter.

First I would check the fluid level in the brake resevoir, if that looks good than I would suggest that you take it down and have the code read. If the light is on, there is a problem. You need to find out what the problem is.

Did the error code not set the check engine light? You never mentioned the light being on in your first post!

Check ebay, purchased a set for my car, cheap but worked fine.