Mods in sig for 95 Trans Am. Developed a miss a little after I changed plugs. I floored it to 6,000 a few times and it MOSTLY cleared up. Really only does it up high in the RPM's now, but before I floored it, it would do it all over the RPM's even down low. I think I should try TR55's. Before I changed them, it had the TR5ix. Only things I have done are swapped with a good stock coil, and inspected wires at night. Didn't see anything, and coil didn't help. Plugs have about 60 miles on them.

 

If they were too cold, they would not be burning off the deposits, so they would be full of carbon. And cold plugs would be likely to work better under high load and poor under low load cruise conditions where they would load up. Since your problem started with the plug change, it could still be related to the plugs or wires. If you dropped any of the plugs or whacked them with the ratchet or wrench while installing them, you could have one with a crack in it. One good thing about NGKs is that they have a fairly wide heat range. Not impossible, but I would be surprised if that turned out to be your problem..

 

I was very gentle while installing them, I did use a good bit of anti seize and I notice it was running all down when I removed them. The car has everything removed and no PS so plug changes are pretty easy. The misfire seems to be getting better the harder I drive. I gapped them at .45 but I doubt that's the problem either.

 

Which MSD do u have? The Opti or the MSD 6AL?

Those plugs look OK but do have some black soot on the plug body. Do u have some extra crank when starting? Just a little that wasnt there when the plugs were brand new? My Champions are like that and the engine popped on when the key was turned when brand new. Now they need a little extra crank to start and im thinking same as u the plugs are a tiny bit on the cold side. The TR55 (stock) and TR55ix are heat range 5 while the TR6 are h/r 6. The NGK w/s says higher number is colder. Without a "hot" ignition box i would go back to the TR55.

Hope this helps,
cardo

 

One more thing is u want to use the "Copper Anti-Seize Lubricant" for plugs to keep the good ground connectivity for the spark: http://www.permatex.com/products-2/p...bricant-detail

cardo

 

Yeah I used copper anti seize. I don't have MSD anything except plug wires. I think I may pull em all back out, inspect and regap down to .35

 

why so narrow of a gap??

 

That's what I read a lot of guys gap them at for 383's. I checked the old plugs (which I never did before) and they were at .35. Doesn't seem like it would make any difference to me. I just re gapped to .35. That black one was no longer. I guess the last couple of times I floored it, it cleaned it off. They all looked really good. Ill see how it runs tomorrow.

 

Drove it today and its not skipping anymore at all after the re gap to .35. I did one run in 4th from 2,000 to almost 6,000.

 

How did that pull feel? Did you scan it?

 

I would think you should use tr6 for the mods you have but that's not always the case seems like. Only way to know is toss some tr55 in there and try to compare. I had tr55 in my car for a while and the plugs were destroyed LOL now I have tr6 in there.

 

Felt good. Didn't misfire or skip at all. I really hate how inaccurate the tach on the instrument panel is. It appears I only pulled to 5300 when it looked like 5800 inside. It started feeling a little funny (maybe) when I got around 5800 (which was actually about 5300) but I need to do it again and see if it was just me. I logged it with SCAN 94/95, but Ill do Datamaster next. Just have to figure out how to use it.

If you wanna see the log I have it on mediafire.