Hello--just a quick question concerning our 1997 2.0L automatic transmission Jetta with ~157,000km:
A few weeks ago, I had a scan and all that came up was that I should replace my O2 sensor.
Two days ago, as I'm driving and speeding up, when my car would normally kick into 4th gear (around 40mph/70Kph), it stayed in 3rd and just revved up like crazy (I could barely get it above 35mph/60kpm). I tried driving in 3rd, then shifting to Drive when the time came, but there was no change. After parking and a few hours rest, it worked fine. The next morning, the same problem occurred (for about an hour or more of driving, as I had to get from one end of the city to the other). Then, when I made a quick stop (~10 minutes), the car was fine for the rest of the day. Took it to my mechanic today, while he was ddriving it, it did the same thing, also apparently went into neutral while in 1st as well on him (it's never done that to me, but I was told that 4th adn 1st are somewhat connected and this could have caused that?). Anyway, as he was not able to diagnose my tranny problem, I'm going to a tranny guy tomorrow to check it out. In the meantime, he checked the tranny fluid adn found instead ofthe nice red color it was completely black (I bought the car last year and am not sure as to when, if ever, the original owner had ever had tranny maintenance performed). I also had an oil changed performed. It hasn't done it since leaving the mechanic's, but the "drive" of the car is not what I feel it ws like before this happened (can't guarantee it is fixed yet).
With your past expertise in this situation, could it possibly be the O2 sensor causing this problem? (my check engine light has not come on since the diagnostic scan a few weeks ago--my mechanic (not a specialized vw mechanic, but a good, trusted mechanic I have known for years) is, as far as i know, so far unaware of the faulty 02 sensor diagnostic reading). Could it be a wiring or computer issue? Or am i doomed to have to replace my tranny? any help/advice is greatly appreciated.