Rough running after spark plug job

[MadMac66]

Hey all

 

Just replaced the spark plugs on my sons '97 986 with 90k miles. We replaced with NKG Iridiums. After trying every trick in the book to get the plug boots out - they were ALL stuck - we got the actual plugs in with no problem.

 

I'm wondering if the gaps were not right on the plugs. Now the start up is pretty lumpy and the idle is quite rough. Not driven it on the street yet.

Any idea 1) what the gap should be 2) check any other areas

 

Thanks

[MadMac66]

I just read that Porsche recommend NOT using anti-sieze on the threads.

(Porsche Technical Bulletin 9102, Group 2 identifier 2870)

 

I used this as I use it on all threads. Anyone ever have this be an issue?

[JE 17]

Newer plugs have a coating which obviates the need for antiseize. I only use it if reinstalling for some reason.

Are certain your coil packs are seated and all wiring is intact. 
If you have a new problem after some work, they are probably related.

[Loren]

If you have a scanner it should be able to tell you which cylinder(s) have a misfire.

[JFP in PA]

16 hours ago, MadMac66 said:

I just read that Porsche recommend NOT using anti-sieze on the threads.

(Porsche Technical Bulletin 9102, Group 2 identifier 2870)

 

I used this as I use it on all threads. Anyone ever have this be an issue?

The EU mandates using only non metallic anti seize compounds for environmental reasons, so the compounds available there tend to act as electrical insulators, which can cause plugs to misfire. Here, anti seize compounds are metallic and therefore both electrically and thermally conductive and work fine on spark plugs.

 

We put a small dab of a high quality anti seize compound on all spark plugs, new or old, and have never had any issues.