95 Jetta Bucks

We got my son a 1995 Jetta III with the 2.0l engine. The price was right (USD 1500 under book value), and we knew going in that it was a bit of a project car. A timing belt, water pump, injector seals, one new injector, shocks, front brakes and rotors, partial exhaust system, shift linkage "adjustments," new instrument lights, and assorted nits and lice later, it's pretty close to roadworthy.

There's one significant problem left. Sometimes (but often), it bucks under acceleration. Sometimes it does not. The weather and temperature have no effect; it can be rainy or dry, cold or warm. Cleaning the coil ground wire helped reduce the frequency significantly. The coil wire resistance is OK, cap and rotor are new, and no sparks show in the dark. No check engine light or new codes (since the injector and seals were replaced, that is).

Any ideas? The coil is about USD 100. I don't mind replacing it if it's a common Jetta problem, but after the foregoing repairs I'm reluctant to shell out for it without a bit more evidence...diagnostic information very welcome!

Also...any other common problems to watch or check for?

Thanks.

JRE

Reply to
JRE
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Reply to
Charles

Try the VWvortex Jetta forum. Lots of experts there.

Reply to
Papa

A mist from a water sprayer might help produce sparks in the dark.

Can you go at steady high speed without symptom?

Reply to
Tom's VR6

If the coil wire were bad enough to cause this, I'd expect to see them dry, but I can try this.

Yes, when it's not failing. No, when it is. You can feel the miss under load when it's failing; it's perfectly smooth when not.

JRE

Reply to
JRE

I was thinking fuel perhaps. A clogged filter would slow you down accelerating and at steady high speed. A marginal rear fuel pump would tend to work a little better with a full tank.

Reply to
Tom's VR6

Oh. I thought that too, at first, and bought a filter we wound up returning after checking the fuel pressure under load. I should have mentioned that the fuel pressure is high (45 PSI, IIRC) and perfectly stable when this happens. Also, at full acceleration and high RPM, when the car's working, it's fine. This happens at any RPM. This seems to rule out the fuel pump, filter, and regulator.

JRE

Reply to
JRE

COIL. Just had mine replaced for much the same symptoms.

Reply to
Bill Kearney

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