my car keeps missfiring,i changed the spark plugs,ithey are brand new champion iridium,im not too sure what brand that is,have apc spark plug wires 9.3 millimeters,they are about 4-5 months old,what could be the reason why the car is missfiring,i gapped the spark plugs as suggested,my car is a 96 eclipse gst but with a 99 gst motor but the turbo is from the 96,the turbo runs good,but it begins to missfire when it hits the turbo around 5 lbs.so i cant run it to its full potential,i have a brand new holley 255 fuel pump.can somebody please help,what should i do,or what can be wrong,list them all if you can,ill fix it all,the car runs realy well when the turbo doesnt kick in,it only missfires whenthe turbo hits. thank you

 

They dont like iridium plugs... change them to good ole classic NGKs

 

What are your mods, Fat? I agree with Sebba about the plugs too. Check your plugs and let us know what's on them and what color the tips are.

 

my mods are pretty basic, greddy type-s bov, k&n intake, greddy evo2 catback, holley 255 fuel pump, brembo rotors, tokico shocks & springs

 

Change the plugs back to good ole NGKs

 

what about my apc ignition wires they are 9.3ml,should i leave them or should i get new ones,if so which wires are the best? Nology wires are about 150.00 online is that a good price,the ngk wires are about 50.00,which wires are top of the line?or which one of the 2 should i get

 

I never knew the gst's didnt like iridium, is that all dsm's or just the gst's??????

 

All 4G63Ts

Stock wires are the best

 

do you have a fuel pressure regulatorto go with the 255lph?

maybe checkfor a badmaf? that screwed my car up and made it misfire pretty bad.

 

I was running a 255 without a FPR.

Im almost positive its the plugs