1 ) approximately 100 miles
2 ) 17965 charge pressure positive deviation / 17545 fuel trim bank 1 add / 17547 fuel trim bank 2 add / charge pressure faults gone after replacement of split intake boot / fuel trim within spec after replacement of MAF
3 ) VAG-COM
4 ) Plugs replaced last week with OE bosch
5 ) Pressure test on boost side / vacuum test for wastegates / tests ok
Now that engine parameters are within spec I am looking at transmission values. The shudder is consistently occuring around 1700 rpms. Torque convertor slip speed is inconsistent during the shudder until it is locked at higher speeds. Vehicle has 188,000 miles on it. Previously checked trans fluid level at correct operating temp and it was ok.
Between intake boot and MAF the fuel trim immediately came into spec.
at idle & partial. Operating within 1.8% to -.08% on all 4 values while driving.
I do have another set of hands
Bank 1 divertor valve is ok. Bank 2 divertor valve bleeds down slowly when vacuum is applied. I did not feel it was enough to effect engine performance.
No P0741 codes in ecm or tcm. No fault codes at all in tcm at any point.
I reset throttle adaptation
Specified vs actual values in channel 115 followed closely dependent upon engine load / max variance was 100 mb
Issue happens on light acceleration. Rpms flucuate by 200 - 300. Almost feels like engine is back firing or stumbling. Observed misfire recognition values. All zeros. Ignition coils appear to be ok visually. I would suspect a coil issue would demonstrate a misfire.
I am also using exxon premium fuel to rule out a fuel issue.