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Misfires in park only??

S

silenthaven

New member
I have a lightly modded 02 gtp and my car has misfires but only in park. Aeroforce says 2 4 6 8 and one time 10 misfires! Why is it multiples of two and why only in park? I get NO light and no codes and gauge doesnt tell me which cylinder is the problem. Since I noticed the misfires I have changed coils and put in 104 autolites. My wires are msd only year old (but they are the kind you have to put together yourself and cut) Maybe wires? If not it wont be cheap im thinking ICM MAF Fuel Injector or heaven forbid a chipped piston? I have a tune with overkill but could that cause a problem he knew I had stock injectors.. At least I hope...
 
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The aeroforce should tell you what cylinder it is, mine did.

And misfire at idle with a modded 3800 is pretty normal, most people don't even know it's happening. I'd lower the plug gap or raise the idle speed to stop it.
 
you need a tuner to raise it. you got a canned tune. cant raise it.

if you had a cam you would have a code for multiple misfires. i take it you dont have a aftermarket cam.

change the icm yet? check over the crank harness?

gap them plugs to 0.50 too.

im no fan of those plug wires either. cheap parts store wires work just fine.
 
Scottydoggs said:
you need a tuner to raise it. you got a canned tune. cant raise it.

if you had a cam you would have a code for multiple misfires. i take it you dont have a aftermarket cam.

change the icm yet? check over the crank harness?

gap them plugs to 0.50 too.

im no fan of those plug wires either. cheap parts store wires work just fine.
Click to expand...

Why not keep the stock .060" gap?
 


Scottydoggs said:
you need a tuner to raise it. you got a canned tune. cant raise it.

if you had a cam you would have a code for multiple misfires. i take it you dont have a aftermarket cam.

change the icm yet? check over the crank harness?

gap them plugs to 0.50 too.

im no fan of those plug wires either. cheap parts store wires work just fine.
Click to expand...

I cant tune it myself so i had to get overkill actually sent it back to be redone couple times that shipping wait sucks! and his turn around wasnt so fast either... No one near me in san bernardino CA that i know of tunes these cars. I have no cam have not changed ICM or MAF or injectors. Maybe fuel pump? I can try cheap wires see if it fixes. Not sure about the crank harness?
I cant tune
 
tunes ok i bet. been ok this long right?

crank harness runs from the cam and crank sensors to the icm. they do fail.

you do any work to it before this started?
 
That youtube bakerxderek guy is from San bernaghetto, this is a pointless comment but it reminds me of him.

Just try lowering the plug gap, if it's only at idle it's really a non issue. They are known to misfire at idle like I said.
 
Scottydoggs said:
tunes ok i bet. been ok this long right?

crank harness runs from the cam and crank sensors to the icm. they do fail.

you do any work to it before this started?
Click to expand...



Junk yard harness work? I have done no big work to it. not sure if its been a thing thats been getting worse where ive missed it under my radar. im not sure. My big engine work was 3.5 pulley and power log last year. Got overkill tune after and Changed accessory belt last summer. since then just installed gauges did brakes...
 




I'll answer the question better, instead of it's just better. You could have google'd this aswell.

The spark has to jump the gap on the spark plug, having a large gap is making it's job harder. The more you mod an engine and force more air and more fuel into the motor, the harder it gets for the spark to jump the gap. There is a better possibility that the compression stroke alone could blow the spark out and not get a complete burn of the fuel. You lower the gap to make it easier to jump the gap and not be an issue. That's a simple way to put it.
 
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