99 cavalier starts but wont run. I changed engine wiring harness off 2000. (Old harness is destroyed.) had to change conectors for injectors and fuse box is slitely different. there is an extra plug (big) next to the plug for fire wall. I prosume it for ABS. Car has not run for about 2 yrs. Sounds good when starts, runs about 3 seconds just wont stay running. Got any ideas?

SOURCE: 1998 Cavalier No Spark in cylinders 1 & 4

ignition mod. grounds,pcm or timing belt could all be it but, I would have to look at timing first.

SOURCE: Engine runs rough. Engine light on.

Try checking the spark plug, and the spark wires, if that doesnt clear things up then try replacing the roter under the distributor cap and check the cap for any corrosen

SOURCE: change spark plugs did tune up on a 99 cavalier

I'm not a mechanic but you should probably change the coils....
it has 2 coils......just follow your spark plug wires the coils are at the end of them........cost around 60 bucks for 2

SOURCE: 00 Cavalier won't stay running.

need to have it scanned to see what codes it has but sounds like a security system problem factory or add on if key has chip in it security prob very likely.hope i helped

SOURCE: Chevy 3500 Express truck. fuel problem?

IF YOU GOT CYLINDER MISFIRE.OR OPEN FUEL INJECTOR.THAT WILL CAUSE THE PCM TO ENRICHEN FUEL MIXTURE.TO ADJUST TO DEAD CYLINDER.WHICH ACT AS A LARGE VACUUM LEAK.THATS WHY YOUR EXHAUST TAIL PIPES HAS A RAW FUEL SMELL AND WHITE SMOKES.