vasman

I ordered a new set of HT0, they are coming on Friday. Meantime, I took the old plugs out (the car was running horrible) and space them to 0.30 to see if it will make a difference.

The car is running fine. I do not know how long this will last, but runs smooth. Try it.

JDWalton

I dont recall what mine are currently set at, either .32 or .35. I might pull em out and drop them to .30 like was stated earlier before I hit the track tommorow to see if theres a difference.

vasman

Its the old style. But with the amount of times I have them in and out (plus anti-siege), they come out easy as butter (as you guys say in Jersey shore).

Unleashedbeast

I'm assuming you are all talking about the old style head/spark plugs pre/mid 2008 model year.

BruceH

Yes, the HT (high thread) design. I have a 2008 but it was built about 3 weeks before they started using the new design.

JDWalton

same, it sucks that the head was used for so short of a time, that there not making it a priority to get alot of variety in plugs.

S197steve

Good info in here guys.

Could this plug issue be the cause of a very slight shudder I'm experiencing at idle? If I'm just sitting at a red light my car will shudder just a shade, the rpms will drop by maybe 100 (at most) and then pop back up. Doesn't seem to affect performance at all and the car drives perfectly fine... this only happens at idle. I have the HT0 plugs that have been on since I installed the Saleen about 10k miles ago in January.

blackout

I had the same issues with my procharger setup. I found that you should not gap the autolite ht0's. They come gapped at .45 and I have had no misfire issues since installing them. This is a problem with many s197's that have gone FI.

vasman

Interesting. I just receive my brand new set of HT0. I was ready to size them. I guess I will try what you suggest, although to me it makes no sense.

How long are you running with plugs sized at 0.45mm?

Unleashedbeast

Then I'm also assuming that the newer head style doesn't share this problem, and the plug choice options are better / last longer.