Ok, '98 GT..... just installed a Pypes o/r X and a Mac flowpath catback yesterday. Before I fired the car to check for leaks, I installed the UPR Mils I had bought. When I finally started it, the CEL light came on... and my buddy cleared the light with his tuner. Last night, car sounded awesome.... but was lacking a lot of low end torque (to be expected).... but today, the car is acting completely different.... still no CEL, but the m'fer is loading up hardcore under any hard acceleration, not just WOT. It backfires and sputters and loads up and runs like a retard and I cant for the life of me figure out why. Another buddy told me his ran the same way and all he needed was a tune-up; i.e. new plugs and wires.... possibility even after it ran fine last night? WTF!......help?
WTF!?
- Thread starter Eng503trk
- Start date
CobraRed_96_GT
Active Member
all 4 O2's are in correctly.... the threads are snugged down and the harnesses are idiot-proof. THe upstream left bank O2 is brand new, we shattered the old one trying to bust it out of the factory H pipe, the other 3 are in really good condition.... just some white discoloration with not a lot of carbon build up and no scorching. I also tried running the car with no MILs and plugged the downstream O2's directly into their harnesses.... still no differences in performance. 
most likely plugs and or COPs 99.99999999999999999999999 percent of all misfires on a 4.6 are plug/coil related.
One time I did run into a bad injector, I almost died of shock.
One time I did run into a bad injector, I almost died of shock.
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