Sorry to hear about your car troubles, they can be a bit daunting at times. The symptoms you described of an RPM drop and lurching can be caused by a fuel delivery problem. The very first step towards correcting this is to replace your fuel filter. I like to do this every 25,000 miles on my own vehicles. You will want to reference your car's repair manual for specific information on how to relieve the fuel system pressure before replacing the filter, or have a trustworthy mechanic do the replacement for you.
I saw that your jetta has about 115,000 miles on it. Have you followed VWs maintenance schedule for your driveline?
Your question stated that it felt like it may be a transmission problem. While the fuel system is usually the culprit, we can check the transmission too. For the transmission, the 1st thing you will want to check is the transmission fluid level. This is best done when the transmission is at operating temperatures. The easiest thing to do is drive to a parts store about 10 miles away, then check the fluid. That way if you need any you're already at the store!
Once you get there, check the fluid level. You'll want to use a clean, white towel or cloth to wipe the dipstick off with. The reason for the white towel is to check the condition of the fluid in your transmission. It should be a cherry red color and not have a "burned" smell to it. If it is discolored or burned you will need to drain the transmission fluid and refill it. (This is a good time to replace the filter mentioned later) If your fluid is in good shape but low, fill it to the "full" mark on your dipstick and see if that corrects the problem. If not heres what we'll do next:
If you have followed your maintenance schedule you will have already had the transmission's internal filter replaced. If you haven't done this yet, I recommend it, as often times this will clear up most transmission problems, and it is much less expensive than serious transmission work.
Most local oil change places offer a "transmission flush." I wouldn't personally recommend going this route, as the filter is never actually replaced, and over time the filter can become clogged enough that no amount of flushing will clean it.
If your transmission checks out to be good and you replace the fuel filter, the final culprit would be the fuel pump. Your fuel pump can be tested by any trustworthy mechanic (Look for the ASE logo!) To make sure that is is putting out correct pressure and fuel volume. Working with fuel injection systems is not something I would advise the novice mechanic to do unsupervised, as the fuel system maintains a constant, high pressure in the lines.
Wednesday, December 19th, 2007 AT 8:45 PM