Hello, I've got a 2010 Toyota Corolla LE 1.8L with 180k miles, automatic transmission. Bought it used at ~176k miles and only had one previous owner, no prior accidents. The guy claimed he regularly changed oil and swapped spark plugs when needed, though I have no official records proving any of it.
About 7-8 months ago, over the winter, check engine light came on with P0171 and P0300 -- bank 1 too lean and random cylinder misfire.
Since then I've tried:
1. Replaced all spark plugs with iridium
2. Replaced all ignition coils
3. Replaced downstream oxygen sensor with exact dealer part
4. Replaced upstream oxygen sensor with exact dealer part
5. Cleaned the original MAF with MAF cleaner
6. Tried two different non-dealer MAFs
7. Replaced MAF with exact dealer part, which is in the vehicle currently
8. Changed engine air filter
9. Replaced oil and oil filter
10. Can of royal purple Max-Clean
11. Ran through multiple tanks of gas
12. Fuel pressure 50 psi
13. Mechanic said coolant temperatures were normal
14. Sprayed carb cleaner all over intake manifold, engine had no sound change
The short-term fuel trim gets to ~17-20 and long-term fuel trim is anywhere from ~9-18.
If I clear the codes, P0171 will come on first, and P0300 will come later.
I took the car to the most reputable mechanic in the area and he said this is highly unusual for a Toyota. After looking at it for ~3 weeks, he said he's going to have to do some "real exploratory" work and that he's "borderline running out of ideas on what to do."
The car runs fine, engine has plenty of power when we push the pedal all the way down, there's no other issues with the car, and ideally I would just ignore these codes. The issue is I need this trouble code to go away so my vehicle can pass state inspection and registration (expires 4 days from now).
What should I do????? Really stuck here and would greatly appreciate any advice.
Cylinder compression test didn't show any issues.
Replaced the fuel pump, no change.
The actual issue was with the brake booster. There was no rust or obvious defect with it (no cracks etc), so it must be some internal defect with the way it was manufactured? With the brake booster replaced, LT/ST fuel trim +/- 1% and check engine light is gone.
He "looked at it" for 3 weeks? About the only thing you haven't replaced is your fuel injectors.
have the fuel injectors tested
https://www.youtube.com/watch?v=XhYEDkpF3Qs
https://www.youtube.com/watch?v=PBt4kOfsX3g
Try a cylinder compression/leakdown test
Hello,
I replaced all 4 fuel injectors with four sets of part 23209-09140 from a Toyota dealer. I reset the codes, drove the car for ~30 mins, and the same bank 1 too lean error code came back.
Took some pictures of the old fuel injectors when I took them out -- the rods looked exceptionally dirty. Here's a link to some pictures: https://imgur.com/a/mwbCn7B
Any idea where I go from here? Does of all of that carbon/gunk buildup on the rods indicate there's something else wrong here?
Thank you.