threepwood

Many thanks for your reply. But I have to point out that I don't have a code 71? However, your comment about a possible faulty EGR valve is really a great thought that had not occurred to me. I will plug it and see what happens, it could very possibly be the cause of the stumble between 40 and 50 mph. I wouid also mention that my research elsewhere tells me that HAC may be some kind of High Altitude Compensation feed back to the ECU computer. Although I have not been able to find where this sensor is located, as it is not mentioned in the Lexus repair manuals.

Check engine intermittently comes on and goes out. Code came up as 35, intermittent short in HAC. What in the world is HAC? Also, although it never came up while driving, the OD light was flashing at the same time as the engine code. It's either code 36 or 63, I can't tell. Symptoms are a terrible stumble when accelerating from 40 to 50 with a hot (normal temp) engine. Cold everything is fine. Any clue to decode these would be greatly appreciated. Thanks.

Just thought I would update you on my final solution. No amount of grease, penetrating oil, etc. anywhere on the door or gearbox could stop the noise. So it is the motor. Thanks to paulo57509 for the rockauto info as it told me I should exchange the motor gear assembly with the rear left door assembly and not the right as I had planned. Bottom line, the noisy motor gear assembly is now installed in the rear left door that no one ever uses and the silent one from that door is now installed in the passenger side right and works quietly again. One little quirk. The leads on the motor from the back door were shorter than the leads on the original motor so i had to make a 6" jumper in order to make the connection. No problem. Thanks again to all for the help.

That is my worry, that the noise may not be coming from the motor gear assembly. I'll try it. thanks.

Many thanks for your quick response. I will try exchanging with the back window and see what happens. Will let you know.

Suddenly and for no apparent reason the passenger side power window screams like a banshee going up and down. I have removed the regulator, removed the gear cover, greased everything insight with PB blaster and wheel bearing grease with no change in sound level. Any ideas? My thought is as a last resort I would try to exchange the motor gear assembly with one from the rear window which is never used. Don't know if that is possible. Really curious if anyone knows what stops the window when its fully up or down ( limit switch? torque switch?). Any suggestions would be appreciated.

This is my final post on this issue so that hopefully, no one else will have this problem. After much reading of the maintenance manual I went to measure the air flow temperature sensor resistance today (part of the Mass Air flow connector) and found that apparently when I reconnected it after installing the starter one of the 2 pins bent over, not making contact or maybe making very poor contact. Why this did not throw a code 24 is beyond me, but it never did. After straightening the pin and reinserting it several times to make certain it had good contact the car has been running perfectly, hot or cold. My take on this - electronic fuel injection is to bleeping complicated, give me back my holley or carter quadrajet carb :) :) :)

Ok, so I measured the resistance of the temperature sensor with the engine hot. It measured between 260 and 310 ohms. I think this is normal. It did drop to 150 at one point but I think that was my loose wires and not real cause the engine kept running. So I decided to check the check engine code just to make sure it was the sensor disconnected code. It was, 22. But to my surprise it had a second code, 15. 15 is some kind of igniter fault which could, according to my book, shut down the fuel injection system., and that is possibly what is happening, as the engine just shuts off. I guess I'll be checking for loose wires this afternoon at the igniters and coils.

Yes I did. It's takes a 17mm socket and the pipe plug is just above the thermostat. Unfortunately, I've made that mistake before :). And when I did, back many years ago, it did overheat. So good thought, but not the current issue. I'm running the car right now with connection disconnected and plan to get a resistance reading on the sensor after it warms up. I'll post it later. thanks.

PS - I already changed out the ECU with my spare and it didn't make any difference.

Ok, now it is getting even more strange. I did find the hose between the ISV (idle speed) and inlet snorkel cracked, so I replaced it. Idle came down to a slightly more reasonable 1400 rpm in neutral. still 1000 in gear. But 30 minutes out car still died and this time would not restart no matter what I did. Temperature was normal warm, where it always runs. Left me stranded a mile from home so I just walked home, waited an hour, then went back to try again. Would not start no matter what I did, but that new starter motor really is getting a work out. Now here's the strange part. On a lark, I pulled the temperature sensor wire to the computer. Car started up immediately, check engine light on, and I was able to drive it home and it ran fine !!! I believe once you pull the sensor the computer runs on a backup program. So somehow, it appears the temperature sensor is shutting down the car even though it is not overheated ??????????????

Ok, so let me tell you what I have done. I fixed the check engine light, it is working perfectly. Disconnect the temperature sensor to the computer and the light pops on, replace it, light clears. Therefore I believe the O2 sensors are not the problem because there is no error code. So I tore the engine down to the starter again and all i found wrong was a water leak from the new gaskets I used on the intake manifold, possibly into one of the cylinders but definitely on top of the engine in the bay where the starter motor lays. I did not use a sealant the first time as the gaskets I disposed of did not have a sealant on them. I, once again, put everything carefully back together but this time using a sealant on ALL gaskets. And, because I had a new spare, I replaced the throttle position sensor with a new one. For a week, the car ran perfectly, hot or cold with one exception. The idle speed in neutral was 2400 rpm. In drive it would drop to 1000. Today, for no apparent reason, at 40mph hot 2 miles from the house the engine just quit. I tried to restart from neutral while rolling but it would crank but not start. I was able to pull onto grass, put it in park, turn ignition switch completely off and back on and restarted the car! I then drove it home, left it in the driveway idling to go get the mail and by the time i got back it had stalled again. but from park, recycling the ignition switch, it started right up again. I am at a complete loss to explain this. Any thoughts would be greatly appreciated.

Sorry, I wasn't clear. I'm going to remove the thermostat to force the car to run cold and prove it is engine temperature dependent. If it still wacks out running cold then it is time and not temperature dependent. I don't think it is, but this would prove it. The only problem I have with the O2 sensors is I don't understand why changing out the starter would cause the O2 sensor to fail and it did not do this before the starter replacement. But the O2 sensor is a good thought and I am keeping it on my list of possibilities. Thanks again for your comment.

Thanks. I guess I'll just pull the thermostat and see what it does. I can't read any codes because, for the second time, the clock display has gone blank.

So, the starter has been replaced (by me) and it starts great, even appears to have fixed what I thought was a battery issue but I now know it was the starter motor. Unfortunately, even though I am 100% certain I put every thing back (there were 45! connections that I labeled and am certain I reconnected) it has a new problem. Cold, it runs great. Accelerates perfectly, maybe better than before. But when it reaches temperature it stumbles and misses badly whenever you try to accelerate. It did not do this before the starter replacement. At first, I assumed that since I cleaned the EGR pipes (which were solidly plugged with carbon deposits) while i had it apart that the EGR valve was now dumping to much gas back in the intake. So I plugged the vacuum hose to the valve, no change. Then I put a solid blank plate between it and the intake, just in case it is leaking, no change. Then I decided to try and trick the computer into thinking it was always cold. I pulled the connector off the temperature sensor under the right hand ignition coil and put a 2k resistor accross it. This also did nothing and was quite surprising, as the temp gauge on the dashboard still functions normally, showing the car heating up normally. So the temp must be coming from some other sensor??? I just don't know of any other system that is bypassed cold and kicks in hot. New problem. With foot firmly on the brake and car hot and running, would NOT come out of park so I could leave the store I was at. Had to use the override button to unlock the shifter. I replaced the ECU with a spare one that I had replaced the capacitors in long ago and this problem went away. I think this car is just begging to go to the junk yard. Next step, maybe pull the thermostat so it actually is forced to run cold all the time ??? Any thoughts would be appreciated.