Last week I installed my new set of coated Pacesetter headers, MSD wires, and Bosch Platinum plugs. Now when accelerating out of corners with the revs low, or when I hit the gas without downshifting, it stumbles like one cylinder is missing. If you get the revs higher so the load is easier on the engine it does not do it. Does this have anything to do with the headers/plugs/wires, or is my Optispark giving up now that its got 90k miles on it? Any help is appreciated as I am at a loss of what to do.

Adam

 

yes.. either that or the opti..
check for wires upagainst ur headers.. make sure all boots are on tight.

 

yes double check your wires,at the plug and the opti.The coil wire also.

 

This is a case of spark plug wire grounding. Somewhere your wires probably burnt through on your new headers. This is the exact thing that happened to me.

 

Ok, what if I've already checked the boots and the wire condition (I have), and they are still ok. Then is it the Optispark or what? It will also miss intermittently at idle, just one cylinder though. Still puzzles me, I'm about to take it to the dealer to see what they think.

Adam

 

hate me for saying this but my guess is that one of your plugs is bad. if you didn't have the problem BEFORE the mods I doubt its your opti. Opti doesn't really just GO OUT, I think it slowly goes away like a clutch. I think mine is on its 1st leg and about once every 2 weeks it will idle low around 750-800 RPMs. Then it will be fine for awhile. I'd check all the plugs, that is my 2cents

 

burnt plug wire. same thing happened to me the day after my header install. just like you i couldnt see a thing wrong with them until i checked at night and noticed they were arching those stock metal boots i pulled off the stock wires for added protection. good luck.

 

I agree... most likely a burnt plug wire.

I had a hard time locating my bad wire.... the easist way is to check in the dark.


Start your car at night where there is no light at all, such as your garage. Then you can rev the car and look at each spark plug and you will find the problem when you see arcing against the block or headers.

 

It is most likely not a wire gounding out if it only does it at a low RPM. Thres is not enough currnet going throught the wires at lower RPM's to cause an arc unless the wire is severly burnt. The wire, if burnt would show a "arc" if looked at in a low light situation. But if it is only cutting out when the RPM is low, check the Opti, if not it has to be a plug or wire.

 

My bet is it is one of those HORRIBLE Bosch Platinum plugs.
Bosch Platinum plugs are great for low-performance daily driven low-compression cars. They are absolutely awful in a high-compression or turbo/blown car. The electrode is very fine and it erodes into the insulator quickly in performance applications. Trust me, I have seen this on two LT1's (one mine), several 5 liter Mustangs (one mine), and on a Thunderbird SC.
I learned the hard way.
Now I run either AC Delco or NGK plugs exclusively.

 

Before you go buying parts do the simple and free look under the hood in the dark and see if you find any blue flashes. Even with new wires .... it can happen. It did to me and the wire looked fine but was arcing to one of my header tubes.

 

Well, I inspected the wires in the dark and saw nothing. All of the wires are far from the header tubes. The closest one is still 1/2in away from a tube. So then I jacked up the car and looked at the connections to the Opti-spark. One of the boots had come off slightly on the passenger side because I guess I had tugged on it too hard while routing it past all of the pulleys of hoses. So I thought I had it fixed but when I started it the same old crap . So anyway, I suspect it could be the plugs but I give up. It's going to the dealer tomorrow, and I will prepare for the usual $500 bill for whatever they do. I'll keep the story updated.

Adam

 

I wanted to add an update to my saga with the headers/plugs/wires. The dealer checked it out and determined that the opti-spark, and wires were ok. They agreed with the opinion of a previous post that it is one of the Bosch plugs. So, I will be installing a set of AC-Delco's on Monday. I should have known to avoid the Bosch plugs because I had to put one in my Thunderbird SC temporarily once and it made the car run crappy the whole time it was in there. Well anyway, I'll post a hopefully successful update after the plugs go in.

Adam

 

update?

 

I hope that changing to AC Delco plugs works for you, but my problem occurs with brand new AC Delco plugs. I'm beginning to think that my problem may be that the optispark was installed incrorrectly. I think there may be a slight oil leak that gets worse when the car heats up and interferes with proper spark. Of course this theory doesn't seem to explain why it appears to be fine at WOT?