I have recently put a 125 shot on my car and switched the plugs out with ngk r5671-a7 (stock #4091). The thing has not been running right since. I gapped all of the plugs at .032" and triple checked the plug wires.... Now it is running terrible....

So my question is, Has anyone had a similar experience with these plugs or nitrous plugs in general???

If so, what did you do to fix it???

I am planning on throwing a set of NGK TR6s in it tomorrow to see if that will make a difference.

It starts and idles fine, but there is a lot of pinging and it seems like it has a dead miss.....




Any help is greatly appreciated.

Thanks!

 

I wouldn't think that those plugs would cause that much of an issue. Sounds to me like you may have some arcing between wires and/or one of the boots not connected firmly or you have a wire crossed.

 

Isn't that plug a touch hot for your mods? I think it's half a heat range hotter than a TR6.....

 

I've been running tr55s since I built the engine. Ran fine.

 

Those are the wrong plugs for your heads. Those are for an aftermarket head. The reach is longer at 0.75 inch and is a gasketed plug.

If you are stock heads you need a tapered 0.708 reach plug like the TR6.

 

Colder in fact with a heat range of 7, so 2 steps colder then a TR55.

 

Quote: Those are the wrong plugs for your heads. Those are for an aftermarket head. The reach is longer at 0.75 inch and is a gasketed plug.

If you are stock heads you need a tapered 0.708 reach plug like the TR6.





Thanks! I will try the TR6 plugs tonight to see if that makes a difference...

 

So I tried the tr6 spark plugs to no avail. Same issue. I followed the stickied method for diagnosing a bad opti. All signs point to opti. I will change it today and post my results.