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Strange Passat transmission problem

I took my 03 Passat V6 automatic (98k) in to get one of the Catalytic converters replaced, as it was leaking and the check engine light was on. I’ve used this shop before and they seemed to be competent.

But when I drove the car away, something kept grabbing the car, like the transmission downshifted (although it didn’t). The entire car jerked or lurched strongly. This occurred every few minutes.

I drove it back, slowly. The shop had no idea. They “reseated all the connectors that they went near” and that fixed the problem, apparently. Been OK for a few weeks now. They had no idea what happened or what they did to fix it.

I had noticed similar occurrences every since I owned the car, but only about once a year or so. My guess at the time is that the transmission got confused, for example, if I stepped on the gas just as it was upshifting, so it had to do several shifts together, or something like that. But a similar lurch. Of course the dealer could never find anything.

Any ideas?

thanks

I think that’s way to vague to really try to say anything definitive. But if you really think that it is the transmission acting oddly (as opposed to the engine) then a couple of things that 1) have electrical connectors that can easily get disturbed during other work, and 2) play an important role in what the transmission does are the throttle position sensor and mass airflow (MAF) sensor (and/or MAP sensor depending on how the vehicle is equipped).

I’t’s not the engine, as far as i can tell. I don’t see how the engine could cause the whole car to jerk and then resume speed as it was before the jerk. First time it occurred I thought someone had hit me.

One more piece of info: the jerk occurs when you let up on the throttle.

Engine misfires can create jerking and are often mistake for transmission problems.

Since it is apparently not a problem any longer you’ll just have to wait until it is acting up. Unless the check engine light is on - is it?

Check engine light never came on, and the jerk was much more than a misfire. First time I though I had hit something, it was so drastic.