Hello I posted this about a couple weeks ago but got no responses so I Hope someone will be able to help me here.

i have a 2003 Chevy blazer 4 door RWD and recently have been experiencing an occasional misfire, exclusively at highway speeds. Idles great, accelerates great, but when Im cruising 60-80 mph Ill have a real hard misfire occasionally.

ive replaced the distributor, intake gaskets, fuel injectors, ignition control module, ECM, MAF sensor, and a whole bunch of other things. Basically everything attached to the motor. It ran great for a while but lately has been acting up. Codes came up for P0022 “camshaft position control” and P0200 “fuel injector circuit malfunction”.

I checked the connector for bent or loose pins, checked the wiring harness to the best of my ability found no nicks, checked all grounds, and I took the throttle body off and used a borescope to inspect the fuel injectors and wiring, nothing looked amiss. Any advice would be appreciated

 

Check wiring harness from ECM at front of passenger exhaust manifold. Mine once got out of place, burnt through the wiring, and caused the P0200 with occasional misfire.