I have a 2004 VW Jetta 2.0L with approx 49k on it. About 4,000 miles ago while driving on the highway at about 75mph my car lost all acceleration, the rpms dived, pumping the pedal had no effect but I still had all electrical power and no check engine light. After this initial occurance it would happen everyday or so but it was so intermittent that it was hard to diagnose. So I tried the usual, changed the oil, air filter, fuel injector cleaner, high octance gas etc with no effect. Now, not only does it do this on the highway from time to time but when Im taking off from a stop light it will accelerate and then just dive down in rpms. ANd this happens after I’m completely off the clutch. Im by no means a newbie with a manual. I can’t always duplicate it on take off. I’ve visually checked all the vacuum lines and they seem fine. I’ve searched the internet with no luck. Do I have a bad fuel pump, fuel sending unit or something worse? Thanks for the help – Jeff
Sounds like fuel starvation, perhaps from a clogged fuel filter or failing fuel pump.
High octane gas would do nothing for these symptoms even if fuel starvation isn’t the culprit.