OU1

Do some research on your EGR Control solenoid it may be receiving to much O2 because it's not functioning properly. Is there any other previous work you've done?

Thanks for the response, unfortunately after doing some googling of the website numerous people have reported this site/company as a scam. Only found 1 positive review about it. As much as I need the harness I can't bring myself to chance it.

I'm having this same issue on my 94, biggest mistake was throwing parts at it, I'm in for about $500 with no real fix. I'd spend the $100-$125 go to the dealer and get a full vehicle diagnostic on it before you spend anymore money. And if your not mechanically inclined I'd recommend taking it to a knowledgeable mechanic to have it looked over. I'd recommend looking at your EGR Control solenoid it may not be re-cycling properly.

My engine wiring harness is pretty much shot, the wires are brittle, and the connectors are breaking from wear and tear. I've searched around a bit on Google with little luck so I'm seeing if anyone knows of a company, website, person that does complete engine wiring harnesses for a decent price for a 1994 Lexus ES300. I can't even seem to find them at the junkyards around me.

Well i replaced all of those items because they needed to be changed anyhow the car has almost 300,000 miles on it so I'm just sucking every last mile out of it, I've done a motor swap and transmission swap on it. This issue arose after I removed the head and rebuilt it. I appreciate your advice, I'll probably get it fully diagnosed.

Will it idle fine while in park? Is it running rough at all or have you noticed a lack in horsepower?

I did some searching on the forums for this issue and tried some of the ideas people had but have had little luck. So here it is. I have a 94' Lexus ES300 that is throwing the code PO171 (System Too Lean) it's lacking extreme horsepower (almost as if it's in limp mode) specially when im going up hills. I've replaced the MAF and cleaned the MAF connector. I replaced all the O2 Sensors, spark plugs, and fuel injectors. I sprayed the upper and lower air intake with starting fluid in an attempt to hear the engine Rev but it did not. The upper and lower air intake both have new gaskets. This is where I'm at a loss and I'm hoping someone has any other ideas to try out before I throw in the towel and take it to a mechanic to have them do a look over.

I thought perhaps an air leak but after spraying starter fluid around the intake and hoses I know that is not the problem. I will look into the coolant temp sensor. Perhaps their is a connector I forgot to plug in. Had to dismantle half my motor to get the head out, obviously did not take enough photos haha. I appreciate the help.

Well my vehicle is running extremely rough, idles at just above a 1, and I have to turn it over 2-3 times to get it started and Rev the engine for about 3-5 minutes to keep the car from dying. The acceleration is extremely sluggish and it seems to be lacking horsepower pretty badly. I thought it might be a fuel issue but once the engine is warm it will start first time, and only runs rough on occasion at that point. I've been searching for answers to this problem with little luck and I thought it might have been this plug.

A knock sensor is used to stop knocking of the motor when it happens. Reducing rough idling and what not. Not using the correct fuel could be the issue. Most posts and videos I've watched on this say it's usually the knock sensor wiring that is the culprit. From what I understand knock sensors don't usually go out unless the motor has a lot of miles on it. I suggest if the correct fuel does not solve this problem then start looking at the wiring and connectors.

When my vehicle had this issue it was a bad VSS, my ECM was unable to read how fast I was going or even moving at all so it either shifted into the wrong gear or just didn't move. I agree though find out what your codes are. A flashing O/D Light is the same as a check engine light only its specially telling you the issue has to do with the transmission whether that be a disconnect in communication or an internal issue with the transmission.

Sorry for some reason it did not notify me that you had responded. As for the shifting cable it's the wire that's running over the driver side of the motor and connects on the front part of your transmission between the bottom of your radiator and transmission. There should be a cable that is connected to an arm that is attached to your transmission. The arm is what controls gear shifting within your transmission. And for the ECM go to a junkyard and pull one or have 1 pulled. There are a few different vehicles you can pull it off of. Look for vehicles between the years 92-96 that have a 1mz-fe motor in them. Replacing an ECM isn't terribly difficult. It's located behind your glove box couple screws and some wiggling will give you access to your ECM

Did this issue ever get solved? I seem to be having a similar issue. I have to crank the engine over 3 times to get it to start, and romp on the throttle to get it to stay running from a cold start. Once the engine is warm it starts in 1 try. However it is lacking a tremendous amount of horsepower almost as if it's in limp mode. And on occasion coming to a complete stop it idles really rough. And when in park is idling above a 1.

So I had to take the head out of my car to inspect it to ensure it wasn't damaged after accidently dropping something in one of the lifters. I put it all back toget her but I have a connector running off of my wire harness that I can't seem to find the home for. I'm working on a 94' Lexus Es300. Pictures are posted hopefully someone can help!

I had a similar problem, my 94' was throwing the PO500 code. and was having a rough time shifting and over revving itself. When I replaced the VSS it only temporarily solved my issue. in the end I had to do a transmission swap as I found that my transmission gears were toast. and my transmission would randomly shift into 1st or 2nd going 60 MPH down the highway causing my RPM's to redline within seconds. have you attempted to replace the VSS? and inspected the VSS plug and wire for any noticeable damage? also have you inspected your shifting cable to insure it hasn't slipped? have someone shift your car through the gears while you watch the shifting cable to see if it is even shifting through the gears.

So I was attempting to replace a knock sensor and neglected to empty my antifreeze out before doing so. I believe the antifreeze may have washed a foreign metal object into my piston. When I start the car all I hear is metal rattling around. I am now getting ready to remove the head that I believe the metal object is in, I'm to the point of removing my timing belt but I'm concerned the timing belt is going to move when I begin loosening the pulley. so I'm wondering if there is a guide on how to reset my timing if and when it moves after removing the timing belt so I can get it back to top dead center when I go to put it back together. Any help, or suggestions would be greatly appreciated as I've never done much work when it comes to the timing of a vehicle. I'm working on a 94' Lexus ES300.

Update: I pulled a wiring schematic for a 96' V6 Camry and found it. Cars up and running better then ever after the transmission swap and proper wiring. I appreciate the input, it was very helpful. Cars got 300,000 miles and I expect to get 200,000 more now! Drives like a dream.

Unfortunately where I live we don't have a wrecking yard. We have a junkyard but they pull all the parts for you. I was hoping someone had a 94' they could snap a pic of it for me.

I did a transmission swap on my 94' Lexus ES300. And after getting it all back together is realized I had pulled one of the plugs out with the transmission and separated the wires from the plug. I am now attempting to rewire the plug but I'm not sure what color goes where in the plug. I believe it's the speed sensor plug as my speedometer is not working and it won't shift into overdrive. Anyone have a picture they can post of the proper wiring to the plug? Or a wire diagram of which ones what and where in the plug it goes. I've posted a couple pictures of what I'm talking about incase I'm wrong about what the plug is.

I'm in the process of swapping my transmission out I've been unable to find much information about it. So I'm wondering if anyone's got a guide to do it, a schematic, suggestions? From the looks of it I can bring it out from the top using a cherry picker am I correct in assuming this is possible? and if not do I need to drop my entire engine with the transmission to disconnect it? I have a 94' ES300, I purchased a junkyard transmission out of a 97' Avalon as they told me they were interchangeable with the converter. Any information, help would be greatly appreciated. Thank you.