High fuel trims.

[Dustin]

Car is a 2003 Mitsubishi Lancer evolution 8. Intake, exhaust is done.
At idle my stft is 4.5-10, and long term is 12.5
If I raise the rpm ft get even higher.
Both b1s1 and b1s2 o2 ffluctuate. I can’t find any vacuum leaks. I have recently fixed b1s2 o2 sensor because it was reading zero, and spark plugs for the p0300 code I had and cleaned the maf. It still seems to have a mis at idle but does not set a dtc. Now it popped a p0171 at idle for stft at 17. Any help is appreciated.

Topic

[dan]

how does data look for manifold air pressure, how is fuel pressure looking?

[Jake Burch]

I was thinking then same thing manifold pressure sensor.if the computer thinks there is boost when there isnt it may be retarding the timing and running it rich.Have you put a fuel pressure gauge on the rail to make sure your regulator is working pro properly?

[college man]

see if this helps.

http://www.justanswer.com/car/1iav0-2002-mitsubishi-lancer-oz-rally-map-sensor-meter-the-fuel-pressure.html

[none]

Assuming you’ve got a MAF sensor, look at the bellows tube between the air box and the intake. If it’s loose on either end or got torn open, you’ll get similar fuel trim problems.

[Mike]

[quote=”Mr Talon” post=122790]If I raise the rpm ft get even higher.[/quote]

I’m assuming this is with the car stopped and no load. I’ve got a few questions.

What does the STFT look like while boosting/doing a pull?
Do you get any misfire while boosting or just at idle?
Is there anytime when driving it that it misfires or runs badly?

[Author]

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