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Discussion Starter #1
Maybe someone can give me some ideas on the miss my car has........

I bought the cobra used with 60k on the clock, and it started missing slightly under loads at low RPM..(usually 5th gear). it got to the point where it started misfiring totally on one of the cylinders. I took it to a ford dealership and they told me that it was the plugs and wires that needed changing and that it would cost me almost $700... needless to say I changed the plugs and wires out to Ford racing 9mm wires and NGK TR-55 plugs. It fixed the problem with the bad miss but still misses slightly still under a load. I put on the Accell coil packs to see if it solved it and it didnt.

Last night i decided to open it up a lil. I did a launch in 1st, shifter at around 6200 and then once it got over 6k rpm in 2nd it seemed to start missing extremely bad on one of the cylinders. The engine had no pull once it did that. I got off the throttle immediately and didnt try it again. I have had the fuel filter changed about 1month ago so i dont think its a fuel related problem. I am going to pull the wires back off and reconnect them to make sure everything is connected good. Is there any compound i need to put on the plug boots that i should have used?

Thanks a Ton
Scott
 

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Missing

Pull the oil breather cap while engine is running...look for anything out of the ordinary..good luck!
 

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Re: Missing

Siskywolf said:
Pull the oil breather cap while engine is running...look for anything out of the ordinary..good luck!
curious, whats suppose to happen when you take off the cap? i was having a slight miss also and it turned out to be my plug wires.
 

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if u see smoke, it could be some bad ringlands. however, if u changed your wires, i don't think its related. make sure your fuel injector is clean. try maybe running some fuel injector cleaner through it
 

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Discussion Starter #6
99svt32v said:
if u see smoke, it could be some bad ringlands. however, if u changed your wires, i don't think its related. make sure your fuel injector is clean. try maybe running some fuel injector cleaner through it
I dont see any smoke at all at any point in time. I have ran a couple of fuel treatments through it, Lucas fuel treatment, Gumout (by penzoil), and i ran some Marvelous Mystery Oil, all at different times, never mixing 2 different ones togethor. I talked with a friend that runs a Express Lube and we may run one of their "professional" fuel treatments through it tomm.

Thanks for everything so far guys.
 

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I used the clear Ford silicone dielectric grease on mine where the wires plug into the coil packs. Removed the old brown wheel bearing or chassis grease that someone else had put on before me. Also looked like there were some lint or fibers that were long enough to create a path for the spark to short out. My miss went away after that.
 

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Check your Fuel Pressure. I had a problem that has similar symptoms, high RPM miss. Turns out my FP was only 20psi at idle :eek: It was the hose connected to the fuel pump, it had come loose. I was shocked that the car even still ran with such low FP. You should see somewhere between 35-40psi at idle ( I think) with the vacuum line removed from the pressure regulator. Good luck.
 

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Discussion Starter #11
JMR_96Mystic said:
Scott: When you changed the plugs, were any of them fouled? What gap did you set the new plugs to?
The plugs I pulled out were the origional motorcraft AWSF32PP plugs that had 60K+ miles on them. They were way overdue for changing. Apperently the car had been run fairly hard before i got it. I noticed a couple of them were in rough shape but i cant remember which ones.

As of right now the miss is gone. I rechecked all the plug wires and put some dielectric grease on them. then i took some throttle body cleaner and sparyed the TB out some (made sure it was the kind that is safe for TB coatings). that seemed to clear up the miss and made the car run alot smoother. I took it to a friends express lube shop and we ran one of their fuel system cleaners through it and the car now runs better than ever since i have had it. I guess it was something gummed up somewhere in the intake or injectors.

thanks for all the help guys, I really appreciate it.
 
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