Misfire.........still.

[AZK1500]

Hey guys,
As the title says I’ve been chasing down a misfire and have had no luck in finding the cause. Ive replaces my injectors, distributor, cap and rotor, plugs, wires, idle air control, and I’ve also done a compression test and everything came back rock solid. The misfire is not as bad as it was before, but it’s still there. And it’s only at idle. As soon as I give it gas, the misfire disappears. I’ve read the suggested misfire threads, and I’ve not found an answer to my issue. Any help would be much appreciated.

 

[Keepinitoldskool]

More info would be helpful. Is it TBI or vortech. Is it one cylinder or random?

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[Supercharged111]

My money's on Vortec. Can you log which cylinder(s) miss most? Done intake gaskets yet?

 

[AZK1500]

It’s a vortec engine. The most misfires come from cylinder 2. I’ve only done the intake plenum gasket, not the bottom ones between the intake and heads.

 

[Supercharged111]

Those are the ones that like to fail, but usually for coolant. Doesn't the coolant cross over in the front? You losing coolant but not leaking?

 

[Cheyenne]

Those are the ones that like to fail, but usually for coolant. Doesn't the coolant cross over in the front? You losing coolant but not leaking?

What do you mean usually for coolant? I currently have a cylinder 2 misfire and I'm losing a bit of coolant. What does that mean?

 

[shamrock246]

What do you mean usually for coolant? I currently have a cylinder 2 misfire and I'm losing a bit of coolant. What does that mean?

It could be pulling coolant from the crossover thru a cracked portion of the intake gasket into the intake port of #2 causing a miss. I wouldn't wait to have issues with original gasket change them out with the felpro metal backed ones.

 

[Supercharged111]

What do you mean usually for coolant? I currently have a cylinder 2 misfire and I'm losing a bit of coolant. What does that mean?

Shamrock got it. The way the intake gaskets fail is around the coolant jackets, and one of those jackets is right next to cylinder #2.

 

[Cheyenne]

Shamrock got it. The way the intake gaskets fail is around the coolant jackets, and one of those jackets is right next to cylinder #2.

So do my intake gaskets and see what that does? I was thinking it was injectors or something

 

[Keepinitoldskool]

If your going to do the intake gaskets then i would consider getting the upgraded mpfi injector setup and doing it at the same time.

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