I have a 1993 ES300. I got it with only 150K. It had some minor issues, main one being it would stall while driving. It could not be replicated. It would just happen at random. And it triggered no lights. So I changed the fuel pump, fuel filter, and Sea Foamed the IAC and intake manifold. It ran like a champ after that. No issues for over a year. I even drove it across the country with zero issues. It's now at 169K, and its starting to stall out again. I just changed the alternator, (battery was only putting out 4V) and the battery. It's still doing it. Still not triggering the Check Engine light. It will also start back up after about five minutes. Which is weird, and which lead to me to believe it would be fuel system related. The tranny would drop a CEL, right? I'm not sure, never had a car this old before. Any ideas what it could be? Any input would be greatly appreciated. Thanks in advance.

EDIT: Caught it as it happened.

 

Also... The guy I bought it from had a mechanic look at it and he couldn’t diagnose it. I had an inspector look at it last year and he could t diagnose it either. So I went to the web and fixed every causes of the issue I found online. It started working fine. For some reason tho, shops can give me a diagnosis because it throws no codes, and i'm trying not to take it to lexus because i know they're not gonna be gentle when they try to bend me over the counter.

 

Your car is OBD-I meaning the CEL won't come on unless something is way out of spec. You changed all those parts but you don't know which of them was bad or if any of them were in fact bad. Fuel pumps on these cars almost never go bad. When the car dies you need to check for spark and fuel. Have you changed the fuel filter?

You sure the battery was 4 volts? That is basically dead.

 

I did. Changed the filter and pump together just to be safe. As far as the battery, I got it checked at Advanced and they said it was putting out 4.6v. So I changed the alternator and got a better battery. The alternator had never been changed, and the batter was more than 3 years old. figured they both could be a problem.

 

Did you use genuine parts? A dirty EGR valve will cause stalling. So will a flaky igniter, bad ground, a bad ECU etc. etc. not very useful to guess but sometimes you have to use the parts canon.

 

Forgive my ignorance, but what’s the parts canon? I was thinking ECU too, but most of the sites I been on seem kinda sketch

First time having a car this old. I miss being able to just plug in and get the info 🤦🏾‍♂️

 

Parts canon means you are "firing" many parts at the car because you have no idea what is failing. Do you live near a Pick N Pull or other self help salvage yard? Should be easy to find an ECU at said places.

 

I checked on car-part .com there are several 89661-33191 ECU's listed.

 

Righteous! Thank you 🙏🏾

 

Are there any other years compatible with the 93? ECU wise?

 

Technically no, 89661-33190 was used in 1992 but you should try and find the updated ECU and the correct one for your car.

 

The 1992 & 1993 Camry V6 ECU is compatible with 1993 Lexus ES300. The Toyota ECU Number is different but works just the same. (Part #: 89661-06021) Hope that helps.

 

I'm betting that the IACV is going bad even after you cleaned it. I would try pulling one off another car at a junk yard and see if you still have the same problem rather than using a parts canon on brand new parts which can get very expensive. Either that or the MAF sensor is reading faulty and causing it to stall out. I had to replace the MAF on my 93 ES300 because it would not even crank up.