1995 Audi 90 problem.
 

Greetings all.

My mother bought a 95 Audi 90 (non Quattro) with the 2.8 V6 and the four speed automatic. It is, as far as I know, the first German machine in my family anywhere.

The car has 136,000 miles on it, and is clean and in decent shape. The engine starts smooth and runs strong. The spark plugs are relatively new, and the wire set was changed recently. It has a relatively new fuel filter as well.

The car has a shudder between 1300-1500 RPMS. I have eliminated the coils as being the problem by driving down the road with a timing light, pinched under the windshield wiper. Even though it is a wasted spark motor, I checked it on all six wires, and the flashing never falters when it the shudder happens.

In neutral, is runs smooth all through the operating range without a miss or hesitation. It idles nice, though it does occasionally die if it idles too long without pushing the gas.

I even tried putting the car into drive, pulling the parking break, and holding the normal break and spinning the motor up into the trouble spot, and nothing unusual happens.

Going through some repair history I have, similar problems have been reported in the past. Plugs were changed, throttle body was cleaned, and at some point the transmission fluid was changed. I am confused on how to actually check the transmission fluid, as the manual suggest this can not be done with the fluid too cold or too hot. All other fluids look normal, and are normal colors, and do not leak. I have been keeping an eye on the oil, as I had to put in a full quart after she got it.

I've seen many other posts about this low RPM shudder / stutter problem, all for various cars, and no one seems to know what causes it, or how to fix it. Someone mentioned it being like the transmission doesn't know which gear to pick, like it is very rapidly shifting back and forth. I too believe it to be a transmission problem, rather than a fuel problem, but I have no evidence either way.

I can answer further questions, if needed.

Shudder at specific RPM.
 

You may get more of these, I, too have this issue with my engine. It occurs at 2200, and continues through 2500. I just figured it was design neglect on the part of the AUDI engineers. Mine is a '94 90CS with the 2.8 12V and a 5 speed manual trans. I have not read any other threads that focus on this issue.

I thought I'd post an update.

We took this car to a garage and had about a quart (and maybe another half again) of transmission oil sucked out of the system. It has not cured the problem by any means, but the nature of the problem has changed. The shudder is different now, and is much more rapid, but generally the car is more drivable across the RPM range.

The problem only seem to happen in third and fourth in particular, and sometimes gets a caught in second for an extended amount of time, and will eventually shift.

Any thoughts?