crash22

Need some help solving an engine surge issue. Have a 2001 A6 2.7T with about 90k miles on it. When the engine is low RPM and high load it surges. Common situations are stuck in slow traffic (around 40-45) or going up a slight hill. Does it with cruise on as well. Only happens when torque converter is locked.
Testing/troubleshooting:
Have completed boost-leak check and vacuum-leak check. Any and all leaks were fixed. Throttle body boot is new, vacuum hoses are new.
Checked ecu for codes-none.
With VAG com connected in normal driving conditions we can see that the oil and water temps are normal and consistent with the gauges.
Torque Converter is functioning properly locking and unlocking as it should. Slip speed is within spec while in the Reg. position between 30-65.
Symptoms increase as the oil temp increases.
Symptoms are not noticed above 2500 RPM or when the tc is not locked.

Any thoughts?

Thanks








Other info:

Car is up to date with mtx. and the Tip Trany is newly rebuilt.

quickaudi:STFA

mods?

crash22

None. Unless you count the 00032 Tip Trany mod but the issue existed prior to that. I jsut got tired of the quick shift into first.

quickaudi:STFA

maybe the N75?

crash22

hmm..I need to retract my earier post then about mods. I installed the N710 DV's about 5k miles ago. I do not recall if the issues started then because it only is noticed when the torque converter is locked and I have been running with a bad tc until just a few weeks ago. I do not have a boost gauge but will get one to check. Thanks

quickaudi:STFA

try a new N75 valve. also, double check that you put the DVs in correctly.