2004 996tt....have a miss/hesitation under load .Engine idles smooth and runs great until it starts to build boost under a hard pull, also makes a strange noise. Thought maybe coils or plugs but check engine light does not come on. 85000 kms (53000 miles) on engine. Something to do with the turbo system??? Any input would be greatly appreciated.

 

spark plugs and/or ignition coils (replace both now)

 

If that was the problem would the check engine light not come on?

 

depends on how long you let it 'miss'...your situation is very typical of spark blow-out, plugs(gap/resistance) in particular are the issue

 

Just had this issue and coil number 2 was toast. No codes or anything. If you data log it and select misfires for each cylinder you will find out which one.

 

Have plugs, coils on order....thanks for your input :-)

 

Thank you...

 

Make sure u clean your maf. Also gap your plugs at .26

 

Have also ordered a new maf

 

.035" with stock Bosch 7410 plugs is good for most cars, at least up to the 600crank hp mark or so

 

.035 ??? No its not. I had mine at .031 and i was misfiring when i had 16gs. I re gapped to .026 and no more missing.

 

were you running 7410's? I've got a number of 996tt's running on them without issue...even running a fairly fat 1.2+bar tune on k24's with a 'worn-out' .040" is misfire-less...

 

I've always put the in the OEM plugs without touching them. Never any issues...

 

+1, nice having the gap set right out of the box ...I check anyways, always measure out at ~0.034" iirc

 

Bought a set of iridium plugs.....ran them in my 930 with no issues