96 Chevy Lumina Multiple Random Misfire

[Davc225]

Keep in mind, I am 16 and though I have an understanding of cars, I have a lot to learn, but I am eager to do so.

I have a 1996 Chevy Lumina that my father recently bought from a friend for me. The car came with the engine light on and I have a friend with a computer scanner. He scanned and it came back with a Multiple Random Misfire error along with other errors that didn't return after he cleared the error cache. The misfires seems to affect the idol as when I stop I can feel the car jerking. It does it frequently but not every time it is run. Any ideas on what could be the cause?

[oldblu65]

Have you checked the fundamental things such as plugs , plug wires , vacuum leaks , etc. ? Vacuum leaks in particular can create chaos with today's modern electronically controlled vehicles . So many sensors are controlled by a vacuum source and when they get false readings due to leaks , it can really disrupt the normal operations . The plugs and wires ( if original ) should defintely be checked and likely replaced . Things like fuel filters needing replaced . Throttle bodies , the IAC control valve , the EGR valve may need cleaning . The throttle position switch ( if original ) likely is worn and may need replaced , and the list goes on . Could the " jerking " you mentioned be transmission related or is it definitely the engine ? Keep us updated - good luck !

[Tech II]

A quick check would be to pull the ignition wires, ONE AT A TIME, off the coil terminals.....if you find carbon/corrosion on the coil terminal(remember one at a time so you don't get the wires mixed up), you can clean the terminal, but you will need new wires.....

So probably, your best move is a COMPLETE tuneup....use good wires(not cheapo's), use OEM plugs and check gap, replace air and fuel filter and PCV valve, and if the misfire is still there , you will have to do a coil output test on each coil terminal, with a spark tester....

[Davc225]

before the car was given to me, all new wires, plugs, oil, and filters were put in the car. Today, I ran the car in my garage, put it in gear and ran down the road with it, and it worked fine. But yesterday it had been misfiring. It doesn't make sense that it would do it one day, sit in the garage over night, and not do it the next. As far as the jerking, it has something to do with the throttle because the car wont idol when it misfires. It will rev up and die down and do it continuously. Could the throttle position switch cause that? My dad told me it needed replacing.