For about a year now once I get up to around 55-60 if I step on the gas the RPM's will go up shortly, then fall down without me letting off the gas. Its a 95 A4. Anyone got some ideas?

http://members.***.net/joshualabelle/RPM%20drop.MOV

 

are you sure its not just the car shifting? , hard to tell without sound on the clip

 

Yeah, i'm sure it not that. Sorry about sound, i took the vid with a picture camera.

 

Does it do that at any other speeds? and does it feel like it's stalling?

Whens the last time you've had a tuneup?

 

Im pretty sure i know what symptoms your talking about. My 98' acts as if it revs about 500 RPM while I'm steady at about 65-70 sometimes. It's not shifting, my foots not moving, I don't know what it is. I've had a few different shops look at it and they can't seem to duplicate it because it only seems to only do it when the car is hot (driving for about 20 minutes on the highway). I wish I could figure out what it is. The car is great but I can't use her for long highway trips because that "surge" thing can't be good for it. I've had a tune up, coolant cleaning, transmission flush - everything I can think of. If anyone has any more ideas let us know.

 

That's your torque converter locking and unlocking, perfectly normal...

 

no - that's not what it is. the torque converter does not make your car do that at 60 mph.

 

It sure is the torque converter. My car does it, my sisters 94 Firebird does it, my parents Jeep does it, my parents Caravan does it, my other sisters brand new Cavalier does it, my girlfriends Sunfire does it, and every other automatic trans car I've ever driven does it. Yours will too...

 

OK - I will admit that I don't know what it is, but I can guarantee it's not a normal function of a vehicle. I've owned 5 cars and driven countless others on my 14 years of driving and I have never ever had a car that did this until now. If this is "normal", then why does it do it every 45 seconds or so at 65 mph with cruise control on? If you don't really know what it is just say you don't know. But don't come in here and spout some crap about " all automatics "doing it", because all automatics don't do this and it's not normal. If it's normal then don't you think I would have been told this by one of the many high performance racing shops I have been to or maybe the two dealerships I have taken it to. Which before you say they are some "little shop/lots", these are two of the largest Chevrolet dealers in Texas. So get your facts straight.

 

I do have my facts straight. You sir, might have a different problem. But the original poster clearly stated that the problem occured when he stepped on the gas while cruising - never was cruise control mentioned.

And, I don't care how large these shops/dealerships are. Did anyone of them actually duplicate the concern? Or do they not know because they haven't duplicated the concern and don't want to make a diagnosis based on your explanation? I am a Ford Senior tech, and have nearly all my ASE's (including Automatic Transmission Perf and Diag), so I do know a bit about cars. This is typical torque converter operation.

 

It does it with or with out cruise control. It happens anytime the car is at a steady speed between 65-70 mph. It sounds and looks to me to be the same issue as the other member.

 

Regardless, it is the torque converter that is causing the symptoms. Now what is causing the torque converter to lock and unlock like that I can't diganose over a message board. I know very little about GM's electronic control logic, especially trans control. The only other help I can offer is that the lockup parameter is triggered by a predetermined TPS voltage or MAP signal, and sometime a combination. If the torque converter is locking and holding properly at other times there is a good chance the torque converter itself is not a fault. The clutches are almost always either good or bad, and rarely intermittent. You either have a PCM/logic problem, or a sensor is malfunctioning enough to trigger the lock/unlock parameter while still being functional enough to not set a DTC.

If you do take it back into another shop, preferrably a GM dealer as their diag equipment is far superior to anything aftermarket, ask them to monitor the TPS and MAP while driving. If either of the two coincide with the symptom, you've found the faulty system.

One other thought... Maybe you could just disconnect the cruise control cable from the TB and drive it to see if the problem still exists. That should rule out a bad cruise control servo/module.