Originally Posted by jerytherew
Hey there I have an 01 malibu 3100. I just replaced the engine for a friend his motor siezed. now starting it up it missfires and its throwing these codes. one is a coolant fan switch the other is random missfires and maf sensor. anybody have any ideas? thank you
How does it run under load? Single cylinder misfire or multiple cylinders? No leaks or damage to any vacuum lines, PCV breather pipe, intake flex pipe? Injector harness is properly routed to proper cylinders, right? These are sequential so a mismatch can produce a misfire. Sure catalytic converter is not restricted? Is cooling fan 1 plugged in (left side fan)? Does it run with A/C request? COOLFAN1 fuse in underhood fuse block is good? Does it have 12 volts available to it?