i have a backfire at 4000rpms and up, what could be the problem? im changing plugs and wires this weekend could that fix it?

thanks

 

I have had the same problem twice. One time it was a spark plug wire arcing onto the header and the other time it was my opti going out........... Good luck.


Chris

 

the same type of thing happened to my friends astro van...and his problem was that the coil would open under load, so he replaced the coil and the problem was fixed

 

That reminds me. I replaced the coil first and it did HELP but it still did it............ Could go either way. Tryi coil first, then opti.

 

backfire with hesitation (I.e. misfire at high rpm) typically bad plugs. Bad wire makes the car lose power and accelerate really rough, very noticeable at low rpms (assuming 1 wire).

 

Maybe a "bad" wire yes. But mine did it because it would arc onto the header. I am assuming it only did it in high rpms because the lunge of the car made the wire move.......... But thats what caused the EXACT same issue on my car so... Check that just in case.

 

ya, i forgot about the arcing bit. How do you test for that?

 

Start your car at night and look at the headers from all angles.... I tried to look for it one night and didnt see anything.... But it turns out when i pulled it onto ramps, and looked at the wires from underneath... you could see a blue spark arcing from the #7 wire onto the headers........


Chris