Questions and Answers

Volkswagon Jetta Erratic Idle Q. Hi, I own a 1991 Volkswagon Jetta (Worlfburg edition). It's my first car so I really don't want to get scammed with through the roof mechanic prices. Info: 1991 Volkswagon Jetta 1.8 liter Manual Transmission 121,00 miles Fuel Injection no ABS brakes No P/S, A/C, or Cruise Control No rack & pinion steering

Problem: Whenever I shift into a gear, it stalls and I have to press the clutch again so it will move. When I stop in first gear, it will accelerate by itself. Sometimes when in first it will also shake a lot. My Dad used fuel injection because he thought it was the problem. It helped a little. After I use the car for a while it will stop stalling. It runs really well aside of that. Can you please help me? I would greatly appreciate it.

Sincerely,
Tania (first time car owner)

A. There could be a number of reasons for this. But let's start with simple stuff before we go crazy looking for expensive stuff.

The first thing to do is to make sure there are no vacuum leaks. Check all the vacuum lines and make sure they are securely attached and aren't broken or cracked. Remember, a vacuum hose never breaks in sight, it's always hidden behind something. Check the PCV valve and the hoses for it. That is a major cause of vacuum leaks.

Check the electrical connectors to insure they are clean and tight. Sometimes a connector may be plugged together but the terminals don't make contact because they are loose. This is especially prevalent on German cars.

Then I would give the throttle chamber and the IACV a good cleaning. You can find how to do it here: Cleaning Throttle Bodies. That could very well fix the problem. If not, then we have to look elsewhere for the problem.