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tommygunn 03-07-2014 09:52 PM

rapid boost fluctuations!? HELP
Hey I just bought an 02 wrx with a vf48, sti tmic, sti injectors, 3inch castles turbo back exhaust, tuned by efi logics. Anytime it boosts Past 10psi the car stutters rapidly and doesn't pull. The gauge goes crazy between 10-15psi. The air/fuel gauge drops to around 11:1. If I keep it under 10psi its fine and I can rev it out slowly all the way. No clue what this could be. Maybe has to do with the tune? Previous owner says its because of the cold but that doesn't make sense to me. Help please

boo-key 03-07-2014 11:22 PM

549 Attachment(s)
Efi logics has a good tuner if mike tuned it. Sounds more like a mechanical problem.

kirby32rex 07-25-2014 10:18 PM

Possibly could be fuel problem as well

pjkatz04 07-28-2014 08:33 AM

im by no means an expert, but I do know that my '12 behaved the same way immediately after I flashed w AP w tune for the cobb intake, and hadn't actually put the intake on yet. Once I got home and put the intake on, it behaved normally again.

From that one experience, I'd guess that the tune isn't correct for the hardware. Maybe previous owner took off the good sh*t and put junk on/old stuff for the sale and didn't spend the expense of getting it re-tuned.

arcticscythe 07-28-2014 02:23 PM

Sounds like it could be a MAF issue, If the ECU is seeing too much or not enough air and dropping AFR to 11 and bouncing around under WOT then there's definitely something going on with that tune or your MAF. You can try Cleaning your MAF with some MAF cleaner, Be really careful not to handle it by anything other than the connector and be sure it s completely air dried before re-installing. If that doesn't fix the issue then my guess is that the previous owner added or swapped parts without the tune and just drove it like that. Ive seen too many drivers with "performance" parts with not tune making the rest of the tuning community look bad. Your tuner should be able to load on a limp home tune just to test for other issues and while its there they can do a dyno tune and get you running with the full potential of those parts.

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