Hi, we bought a 2002 Lexus ES 300 With 207000 miles. and it had a hesitation when the engine was cold. Once the engine warmed up it drove fine check engine lights. Are bank 1 bank 2 running rich. So we changed spark plugs, fuel injectors. Ignition coils master flow sensor PVC valve. Throttle body fuel pump fuel pump screen and filter We also replaced any vacuum lines that looked cracked or worn..We replaced the two boots going to the Intake. We took it to a mechanic. They did a smoke test said we had a small leak at the oil filler cap replaced it they also said 02 sensors upstream were bad, so we replaced upstream and down stream check lights are still on so we took it to Lexus. They said it was the computer. We replaced the computer and the bank. One in bank 2 are still running rich. I've lost my mind trying to figure this out and spent a lot of money. Do you have any ideas? We've also replaced all of the parts with denzo or toyota parts
spent a lot of money.
yeah that's what happens when the mechanic has no idea what he's doing, changes some parts and pushes you out the door without testing his work. You need a smarter mechanic. One who tracks down the source of the problem instead of throwing random parts at it. And sadly, the dealer aint it. Somebody has to look at the data , analyze it and take the time to troubleshoot it properly.
we bought a 2002 Lexus ES 300 With 207000 miles
You bought a 23-year-old vehicle that is at or near the end of its expected service life. Hopefully you did not pay too much for it.
Once the engine warmed up it drove fine check engine lights.
That means there are codes and freeze-frame data. You could also check live data. What was found?
we changed spark plugs, fuel injectors. Ignition coils master flow sensor PVC valve. Throttle body fuel pump fuel pump screen and filter
Did any of those actually test as being bad? Or were they guesses?
I've lost my mind trying to figure this out and spent a lot of money. Do you have any ideas?
When you buy a decades-old car you have to expect some problems. It sounds like the mechanic you went to is a parts changer. What you need to do is some actual diagnosis. It would be helpful if you would post the actual codes that were seen as well as any suspicious items in live or freeze-frame data.
The codes are p0175 and p0172 The only other thing Lexus said was that they tested the fuel pressure and it was within spec while running and turned off. And they said something was telling the computer to reduce the fuel pressure by 40%.
The dealer is not a good place to take an old car for service
The computer is probably reducing fuel pressure in response to sensors telling it the mixture is too rich. Is there evidence that the engine is actually running too rich, such as poor gas mileage, fouled spark plugs, and sooty exhaust, or is the computer registering a false positive due to another issue?
You can see the potential causes of those codes at the links below. (The codes are very similar and chances are there is a single cause for both.)
https://www.carparts.com/blog/p0172-code-fuel-system-too-rich-bank-1/
The above are pretty complete but an internet search on those codes will likely bring up more possibilities.
It's appears the places you've gone to so far are just reading codes, guessing at the cause, and throwing parts at the problem. The best bet for a solution is to find a good independent mechanic who is able to do real diagnosis digging into the data stream rather than just checking codes and changing out parts. (The kind of diagnosis that Scotty does, or other online mechanics like Car Wizard, South Main Auto, Rainman Ray, Pine Hollow Auto Diagnostics, etc., that perform in-depth diagnostics.)
The codes are p0175 and p0172 The only other thing Lexus said was that they tested the fuel pressure and it was within spec while running and turned off. And they said something was telling the computer to reduce the fuel pressure by 40%.
None of the parts that were changed were throwing codes.