did a lot of reading on plugs for running nitrous and found that most people run either NGK-TR6 or Autolite 104 spark plugs gapped at .035. O'Reilly didn't have TR6 plugs so I bought Autolite 104's. Yesterday, a friend and I installed the plugs, gapped at .035. He accidentally broke one plug while installing it (mentioned after initial startup and a miss was discovered), so we took one of my old TR-55s, gapped it to .035 and installed it in the car to get me by until I could buy a replacement 104. Started the car and checked with Autotap and found no misfire.

Drove the car to work this morning with no problems.

Left work to go to the doctor and once the engine got good and hot, it started to miss at really like throttle inputs. Anything above say 10-15% TPS would run fine though. I assumed it was the one odd plug. After the doctor, I got two more 104's (one extra) and headed back home. Once I got home, I fired up Autotap (laptop battery was dead so I couldn't log in the car while driving) and discovered that every single cylinder EXCEPT the one with the TR-55 is missing. Some more than others, and the worst ones move around (no real pattern basically).

Not sure what to do now... Anyone have a recommendation?

 

How old are your wires? Take a look under the hood in the dark while the engine is running. Look for arcing. I've had good luck with both 104's and 103's on a supercharged engine (with an occasional shot of nitrous .

 

keep your coil in mind. sounds like it could be the problem.

 

There was no miss before changing the plugs. The only reason I changed the plugs was for the nitrous. The car had been running fine with the TR-55s.

The wires aren't very old. Not a year old yet.

There is no arcing anywhere under the hood that I can find. I've looked from the top and the bottom, and at the Opti as well.

I just find it odd that the single odd plug is the one that is running properly.

 

I'd still bet a wire got tweaked either pulling it off to change the plug, or it's laying against the exhaust somewhere. Also, you're gonna have to check that all the plugs are tight.

 

I'll double check the wires this evening if I can. This is not a single cylinder issue. It's 7 cylinders that are misfiring. How I could have screwed up 7 cylinders, I don't know.

 

You're right, it's not likely...but I think you'll find it's one wire that is causing the coil to freak out. The fact that it failed as soon as it heated up really leads me to believe it's a wire issue. Been there, done that a number of times...and me and my buddies are super **** with stuff like that, but it still seems to happen to everyone. Wires on these cars are fine, until you disturb them, then it's over.

Also, how much anti-seize did you use? I've heard of people having problems from using too much. It should be used sparingly...like put some on the plug threads and then use a rag to wipe it into the threads and remove the excess.

 

I went out to the car at lunch, and worked on the driver's side wires. I pulled them all and reinstalled them and each one clicked into place on the plug.

Came home, hooked the laptop up to it and they're all still missing except the one that's got the TR-55 in it (gapped to .035 like the rest of them).

So after letting it cool some, I put another of the TR-55's (gapped at .035 as well) back in it in place of one of the 104's and the miss on they cylinder is gone as well.

On the antiseize, there wasn't much used. Barely enough to give the threads a thin layer.

 

Hmmm...well, if it works, it works...but it doesn't make any sense. Too many of us run both those plugs with no problems. I've never had a problem with either one.

 

When I pulled the new 104's out of the box, they were all gapped slightly larger than .035, so I narrowed them bit. MAybe I'll try to increase the gap slightly and see if they do better.

I just want to be able to run up to 100 HP shot without worrying about detonation from the plugs.

A buddy of mine runs 175 HP wet shot on TR-55's gapped to .045 and he recommended I do the same.

 

Is it okay to mix 104s with TR6s? My local Autozone(s) are idiots... they dont know/understand what TR6s are. Plus they have to cross-reference them. I bought some out of town.
There is an OReilleys a block away and my car is misfiring like crazy. Need a quick fix.

 

I've been chasing the same kind of miss for a week now. I installed my wet kit last week and went to the TR6's from the TR55's. Now I have a really bad miss when the car warms up....only at part throttle. Pops through exhaust and car shakes and shudders. At WOT it seems to run fine. Haven't sprayed yet though. I've replaced the wires but still have the problem...I'm thinking I have a bad plug or two.

 

O'reilly's sells both the Autolites and the TR6's. I don't know of any reason you can't mix them though.

 

I put some new TR55s in the car, with a lower gap and it's running fine now.

 

The TR-55s are okay to spray with? At .035 gap?