Hi Guy's

I have a 1987 928S4 which I suspect has a leaking injector seal.

The previous owner (recently) had the whole intake system reconditioned with new porsche parts however I still experience problems every now and then with what feels like misfiring and erratic idle for about 1 to 5 minutes after startup. When cold or hot.

When I last changed the spark plugs I noticed that one (1) of them was wet with fuel ! I suspect this is my problem . Could this be a leaking injector seal or is it more of a spark thing.

The car has new leads and ignition parts as well as reconditioned injectors and new seals etc.

Any suggestions would be appreciated

It's kinda funny but I found one on my 944 assuming that I had a leaking injector on the number 4. On the next plug change, none of them were wet. I think what happened was upon shut off, there was still a little fuel left over in the cylinder that didn't combust the fuel injected into the cylinder.

a faulty idle stabilizer valve can also cause erratic idle along with a mass air flow sensor.

Its just wierd that only one plug was very wet .

My car has a brand new mass air flow sensor.

It doesn't happen all the time ...about 60% of the time. Once the engine smooths out its fine until you turn the engine off (even for just 2 seconds).

Spark plug wire?

good point! Is the wire touching anything that could be grounding it out?

Were the injectors cleaned and flow/leak tested when PO rewuorked the inlet system ?

I'm experiencing the same symptons. Everything is new: ignition wires, spark plugs,rotors, caps, temp sensors, r&r intake, vacuum lines, oil breather hoses, injectors cleaned.
It idles okay but has a bad stumble/misse. Upon start up it runs well for approx.30 seconds then it goes into stumble/miss mode until oprerating temp are reached. When hot you can still feel a miss but hardly noticable.
HELP! Not sure what to do next if anything.
Thanks

My main question I guess is :

Does anyone think that a leaking injector seal could result in a wet spark plug ?

Bump !

I would be concerned about a potential engine fire.

I would think a leaking seal would carbon the plug from extra fuel, instead of wetting the plug. Sounds more like a plug firing problem on that cylinder.