Quote:
Originally Posted by Jeff@TopGearSolutions
I think we have the same exact symptoms.
I have a very very subtle oscillation on the highway. Particularly around the 60-70 MPH... very very light throttle.
Replaced:
6 Plugs
6 Injectors
6 Coils
Valve Cover / Gasket
Upgraded PCV Valve
All Vac Lines
Aside from being in the tune. The only things that are left for me are Boost solenoids, o2 sensors and walnut blasting.
I've already inspected my intake vales (50K miles) and there actually decent - not clean but decent. I've seen far worse at my mileage. I'm still leaning towards the tune but I may be able to clean it up with the above mentioned.
Right now, I don't think there is a need to spend money blindly trying to fix it. I've talked to Wedge and he think it might be 02's, although my AFR, STFT and everything else appear normal.
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Yes, sounds exactly the same to me. I always drop a gear to get the revs up a bit because it annoys the hell out of me, at which point the additional throttle seems to make the issue go away.
I was toying with the idea of switching to linear throttle for more control, but was concerned it may make the issue more noticeable given the larger amount of pedal travel that I will actually be able to apply very low throttle amounts.
I'm doubtful that it's boost solenoid related as you're not really running any significant boost at that rpm. I guess you could just bypass the solenoids altogether and take the car for a run. Obviously don't boost as the wastegates will never open, but it would potentially eliminate them as an issue.
I did wonder if it was issues measuring airflow at very low load? I've always wondered if a map sensor is less accurate than actually having an airflow meter, perhaps the tune highlights this weakness? But then you expect to see it in all tunes and probably the standard car too.
I'm interested to hear what wedge come up with, please keep me informed of any updates as I would like to try these on my car too. Have you tried logging during the hesitation to see if that can help point to the issue? I haven't yet but may give it a go and see if any of the figures appear to be jumping around.