misfire problem

[tstang93]

every now and and then my car missfires and then it will be fine. i changed the cap and rotor what would cause it to work fine then miss fire

 

[DSGB347]

Once I had that probablem with a plug wire that was bad/arching on the headers. I have also seen it happen with using platnum spark plugs in 302 motors they don't really like anything but good old copper.


I t could also be the something in the emmissions system have you cleaning the IAC idle air control when they get carbon built up in them they can cause some really head aches.

 

[tstang93]

Is that the oxogen sensor IAC and the wires look good and lpugs are ok would it be the mass air flow or is the either works or dont work.

 

[DSGB347]

It could be a MAF. I would try using some sensor cleaner and a Q Tip and cleaning the little heat element on the MAF first just be carefull not to break them the are sensitive and know to collect dirt. They get especially dirty when running cold air/ ram air intakes I would try that before changing expensive MAF units.

 

[tstang93]

i think it started doin it after i over reved the motor after a missied shift now it messes up sometimes and mis fires

 

[DSGB347]

Just because you said you over reved it maybe valve train related. maybe you bent a push rod alittle or wore out a sping on the cylinder head.. Hard to say.

 

[Dino Dino Bambino]

i think it started doin it after i over reved the motor after a missied shift now it messes up sometimes and mis fires

Sounds like a piston might have come in contact with a valve, bending either the valve head or bending a pushrod instead. A compression check will reveal if it's a bent valve, and you can pull the valve covers to inspect the pushrods.

 

[tstang93]

yeh but i dont think that would just go away and come back a valves not gonna fix itself

 

[U2SLO450]

I would clean the maf like they said and have a look at the plugs/wires. You might even have autozone test the dist. module.