I have a 1998 Passat turbo wagon. A couple of months ago, the engine began intermittently shuddering/stuttering. The car/steering wheel vibrate when accelerated. Acceleration is very slow. It may start when started, or just driving down the road. This can last a few minutes/block or several minutes/blocks. It disappears just as quickly as it begins. My garage ran engine analysis and nothing shows. Can’t do anything till they can duplicate, and I can’t cause it to happen. During the occurrence, tach is at 9000 and steady. I use high octane gas. Today, while stuttering the engine just quit twice while stopped. Car has 115,000 miles and otherwise is in excellent shape mechanically (regular oil changes, etc.). Any idea what’s happening?
9000 RPM ??? That should be well past redline.
How old are the plugs? Are they OEM brand and part number?
Any other 16 y.o. ignition parts (plug wires, coil(s)) could be the culprit.
Distributor cap and rotor too, if it has them.
Assuming the tach reads 9000 rpm incorrectly, it sounds like the rev limiter is cutting spark/fuel to the engine.
- 1 to @circuitsmith;
I presume it’s 900 RPM.
This could be caused by one or more of any number of things and it’s near impossible to make much of a guess due to lack of information. Some possibilities:
Ignition miss coming and going; aged plugs, coils, etc.
Fuel pump getting intermittent.
Turbocharger impeller trying to seize up and/or not rotating as easily as it should be. This can be caused by coked engine oil due to oil type, irregular oil changes, and so on.
Assuming the routine engine maintenance is up to date. Among the things I can think of, all of them would most likely turn on a check engine light. I’m assuming that light is working and never on when the engine is running. hmmm …so what’s happening?
I guess if this happened on my Corolla I’d do a visual on the EGR valve, make sure it operated smoothly and wasn’t sticking, since the symptoms are consistent with a stuck-open EGR. If that turned up negative, I’d probably get out the fuel pressure gauge.
Yes, tach was 900, not 9000. sorry.
If I came up behind a stuttering Passat at 900 RPMs I would follow the instructions on the back and PASSAT! Sorry. Sometimes I can’t resist.
Most likely the ICM … an easy repair and not that expensive .
It’s on top of the air filter .
ICM? What is that?
Ignition Control Module but do some tests on it first. You can Google the tests for your year car. It’s a couple of voltage tests w key off and on etc. Easy stuff
Ignition control module . It can start to fail without throwing a code . Important that you use the heat transfer grease that comes with the new part . a thin smear is plenty .
Also check the MAF sensor. Does the car Idle roughly also? A quick test for the MAF is unplug it with engine running and if the symptoms go away then there’s your problem. Just a thought