Driveability problems can be caused by many things. And when you have multiple candidates you always want to start with the basics which are usually the most economical repairs. When that doesn’t work, you can come to the Community for help. SureTrack community member alltune had a Volkswagen Passat in their shop that would jerk while lightly accelerating and they repaired several things but still had the issue. They posed the question to the community, and with the help of fellow community members, they were able to resolve the issue.
The following Real Fix summarizes the interaction between them in the community that led to the solution.
Vehicle
2003 Volkswagen Passat GLX 2.8L
Title
Car jerks at 30 mph on light acceleration, replaced transmission.
Complaint
Customer complains that while driving, the car jerks under light acceleration.
Diagnostic Steps Performed/Parts Replaced
Test drive vehicle and it drives fine up to 25, 30 mph then on light acceleration the car jerks slightly. The only code we had are p1570, 17978, immobilizer intermittent. No other codes, the monitors are all ready. Replaced ignition coil, plugs wires and crank sensor. Cleaned EGR. Cleared codes and nothing came back. Yet the jerk is still there. We removed and cleaned the EGR valve. We also smoked the entire system including intake, evap including spraying brake cleaner on and around the engine, wherever vacuum is possible. Nothing, all still the same.
Transmission fluid is very black yet the level is fine. The car has 112k. Is this transmission falling? Or what else could be wrong with this VW.
Cause
Upon further testing found that the transmission was the cause.
Correction
Replaced transmission and vehicle no longer jerks while accelerating.