Been having issues with my ‘01 blazer. First it threw random cylinder misfire with a MAF sensor, replaced the MAF, then came the cylinder 1 misfire, diagnostics and troubleshooting pointed to the injectors (I still had the old style), replaced injectors with upgraded version, now the Mia is slight, only below 1500 rpm, but still throws a cylinder 1 code and a new code p0200 injector circuit. Have checked the plugs, wires, pins, connector, harness, used the noid light, everything seems fine. What is my next troubleshooting step or what am I missing? Also, I don’t know if it’s relevant but my mechanic thinks but the piston rings are letting oil passed and the egr is sucking the vapor and recirculating it to the i take, the thing was covered in oil and carbon when we changed the injectors yesterday.

 

Bent or loose pin in injector connector (open)- or wiring harness melted (shorted) on the front of passenger exhaust manifold or A.I.R.check valve tube. Mine was melted on check valve tube after I misrouted the wiring harness after engine replacement.

good luck