Please take a look at sig for all major work done to my 98 A4. I have begun experiencing a slight surging as I am driving down the road between 35-40 MPH and I let off the gas pedal. If I'm accelarating there's no issues, but if I'm taking off the light at a moderate rate once I hit 35 or so I feel the tranny shift and I let off the gas for any reason then this "stumble/hesitation" almost like the car is about to stall starts to happen. Once I give it gas and go over 40 the surging goes away. Neither gas mileage nor performance off the line appear to negatively affected.:wtf:

I know with the stall converter in place I could expect to see something similar at times but this just started happening. My car has been mdified for over a month now. I have no codes showing- neither current nor history.

As you can see by the sig the tranny, converter, rear diff and gears were all done at the same time. It ran fine until a few days ago. Thanks for any input you folks can provide.

bump, any ideas from the group???

You did not mentioned if and what type of tuning has been done.
Some mods you say were installed a month ago but that also was with colder weather and hotter air will see issues such as engne richer and then too lean on decel

When lifting off gas pedal the PCM goes into decel mode and reduces the injector pulse width to save on gas.
The best path is to use a OBD-II scanner and look to see what happens when in decel and most likely the tune needs to be done or tweaked to fit the car's makeup, weather and your driving style.

Also look to see if the MAF needs cleaning and any air leak from the aircleaner to the throttlebody

Thanks for the response, the car spent 2 weeks getting all of the work done. One of the major things addressed was tthe PCM, it was changed out with a brand new one from GM. It was then street and dyno tuned. It has been running fine and just recently started to experience this "small issue". I will take a look at the MAF, it is the original one so there may be something there. If that doesn't do it then I'll take it over to get looked at by a shop here in the area or may be in a few days when I go up north I'll take to ECS for a look.

Fuel filter,maf wire ? By the way how do you like that 3.42 gear?

What size injectors do you have in there. I have run into proportional fueling issues at very light throttle on some vehicles with large injectors. Sometimes you can fix it with the tune, other times it's a physical limitation of the injector itself.

Lethal Tendencies -Fuel filter,maf wire ? By the way how do you like that 3.42 gear?

I F*@KING LOVE having the 3.42, very noticeable pick up. But I guess the tranny didn't hurt either. Fuel filter is about 10 months old, I just cleaned out the MAF this weekend and nothing.


DynamicTuningSolutions - What size injectors do you have in there. I have run into proportional fueling issues at very light throttle on some vehicles with large injectors. Sometimes you can fix it with the tune, other times it's a physical limitation of the injector itself


The injectors are stock, I honestly did not think that with a sub 500 Hp car swapping injectors would make that much of a difference.

Ok, with stock injectors we can definitely rule out the proportional issue. I would check with your original tuner and see if something shifted (no pun intended :D).