I have an '86 Golf. Recently it has failed two California smog emissions tests - on Nitrous Oxides only, and not by much.

My mechanic supposedly has the air/fuel mixture right (although I'm going to go back and see that it really is) and replaced the gas filter. I put a new rotor and plugs in, and ran an additive through one tankful.

Maybe you need to let a couple tankfuls go by before testing? Also - I've been living in Mexico for some time and using Mexican gas - until about three tankfuls ago... Now it has Premium gas in it...

Anyway, I was just noticing that the car's firing seems unsteady, kind of jerky, and...

I'm wondering if that might be a symptom of needing a new coil? When does one replace the ignition coil - for what reasons?

Another worrisome thing is that when I pulled on two of the spark plug wires they just detached from the connectors at their ends (at the plug end); I screwed them back on - but did I buy cheapie spark plug cables last time, and should I replace them?

Lotsa questions... Any advice would be welcome.... Gotta pass that smog test..

Thanks,

Bob