error codes in '02 GT
 

over the weekend I put in the UPR catted X pipe and some underdrive pullies (they were the piggyback ones... I know.. but that's all my wife would let me get with my allowance). Anyway, I'm throwing codes 0300; 0316; 0301 and 0302. All are misfire? I clear them and they come right back.
0300 is misfire detected at startup (under 1000 RPM)
0316 is random misfire detected
0301 misfire in cylinder 1
0302 misfire in cylinder 2

The car runs great and I can't feel a misfire. Could the pulley / balancer combination be out of balance enough to read like a misfire to the ECU?

Also, I removed the timing adj at the same time and put the magnetic pickup back in the block. Any thoughts or tests I could try?

check your ckp sensor. put your adjuster back on and clear see if it comes back

what is the ckp sensor?

I looked it up last night.. It's the CranKshaft Position sensor