Well my car started missing again. 99 GT, 4:10s, XPipe w/ no cats, flow masters, mac cai.

I replaced coils with some used ones(all tested good on OHM test) I think its got a bad one again, when its humid out it does it most. Before I start checking coils, is there anything else it could be? IM not throwing a code for misfire. I know u can check the COPS with an ohm meter(all read 5.7X and up) can I ceck any other part of the ignition to see what it could be? Seems to do it mostly in lower RPMS/High Gear. I replaced the fuel filter also.

Also, I have been running ngk tr6s since I use nitrous but I believe they may be too cold. I blow a lot of black smoke and run pretty rich. Would a hotter plug help burn off the fuel more?

 

"Blowing black smoke" and running "pretty rich" will cause misfires. Also, how many miles on the plugs?

The NGK TR6 is just a plain ol' cheap conventional electrode plug, if they've got over 15k on them I'd replace 'em just for good measure. A hotter plug would help too if you can't fix the overrich condition...

 

i have the same problem and i cannot figure it out either i have tried changing the coils but no luck yet