I did a search before buying plugs and could not get a definate answer as to what these cars come with. I can now say they are Iridium single tip plugs from the factory. My car has been having a problem especially at altitude and below vtec rpm with surging and no power. It's always on 91 octane but the surging feels just like the computer pulling timing due to detonation. This is why I decided to change plugs... I wanted to try going one step colder on the plugs and see if this takes care of my problems.

I could not find a one step colder plug anywhere and I was hell bent on changing plugs today so I went with the next best thing, double platinum single tip plugs. I figured if these worked I could keep searching for a colder iridium plug and swap them out.

I haven't gotten to try them out at altitude yet but the difference is amazing already.

The idle is smoother, especially when cold. In the first 30 seconds or so, the car has always had a very slight miss. It's gone now.

WOT power feels about the same.

When the AC compressor would cycle on at idle, it would cause a dip in rpms until the computer brought it back up. When it clicked off, a slight rise in rpms until it leveled off. It no longer does this. When the compressor clicks on, rpms are rock steady.

The big difference is part throttle drivability, especially when easing the gas down when the rpms are below 2K and the convertor is locked. This used to cause a little surging and the occasional ping. It's completely gone now and the car feels much torquier and pulls cleaner at low rpms. This was exactly what I was hoping to fix.

This seems very promising for when I take it back up to Vegas and I'll update this thread when I get there. Stock plugs looked pretty good. A little more carbon around the outside than I would've thought and a pinkish color to the insulator, probably fuel additives. This only took me 35 minutes to do, minus gapping. The stock plugs had no antiseize and made a bang when they broke free. I made sure to use it.

I have to wonder about the 100K tuneups. I'm sure the car would still run but I doubt it will be running at it's best.

 

Wow, sounds good. I read your other post about you the whole issue with the altitude/heat causing problems with the TL, so hopefully this makes a difference. How much did the Plugs cost, I might do this

 

I hope you are using NGK or Denso ONLY
Anything else is bad news for us
NGK Iridium or NGK PLatinum

 

You have to understand that "colder" plugs does not change the intensity of the spark. It just have a shorter tip to dissipate heat better, absorbing more heat in the combustion chamber. Best for turbocharged motors. However, it will not burn off carbon deposit or oil all that well . More likely to foul during cold start up, causing erratic idle.

 

Only ones I could find in stock that were colder were autolite double platinums after going to 4 different stores. They're only temporary but so far so good. I'm sure they will be fine. Cost was 3.99 a plug. Since these are temporary I almost got the non-platinums for $1.99 or .99, can't remember, but I tend to get lazy so these could end up staying in for a while if they work.

 

Yes. I have a turbo car that runs 2 heat ranges colder than stock at low boost (19-24psi) and 3 ranges colder for over 25psi boost. With the 3 range colder plug if I drive it easy for too long, the idle gets rough but clears up as soon as I do a full throttle blast.

Looking at the stock heat range of "6" on the NGK plugs, it's a fairly hot plug. I'm sure one range colder won't hurt anything. I serously doubt I'll run into any type of fouling. Besides I think the factory plugs are borderline too hot. The fact that the car runs better with a colder plug, especially under load at low rpms backs that up. Look at the "valve chatter" thread toward the end where the guy nearly solved the TL-S pinging problem going with a colder plug.

 

My bad , I didnt see your sig on the turbo Buick .

 

Which is why I chose my username.