Misfire issues

[Sandman]

I started developing a misfire all of a sudden last weekend. It would misfire at about say 10lbs of vacuum. I changed the coils and now its only in boost. I've also changed the ICM, swapped the wires, and regapped the plugs to. 058 in case it was spark blowout. The only other thing I can think of is changing the plugs out, these are not even 2 weeks ago. I think I have a bad flex but I wouldn't think that would give me the problems I'm having. No codes and the car runs fine otherwise. Any bright ideas?

[Fivefingerdeathpunch]

It misses but throws no code for which cylinders it is?

[Sandman]

Yup

I also noticed tonight coming back from the bar, it doesn't start to miss until the motor actually warms up, that's when it starts.

Where are the engine grounds for these cars located?

[mikedinthecity]

vacuum leak? running out of fuel? bad injector or injector o ring?

[dsmuts]

Are you scanning it? Should the scanner be able to tell you which cylinder is misfiring?

[Sandman]

I'm waiting on a tuner to get here, I'm hoping today. I don't think that I have any vacuum leaks, I shouldn't be running out of fuel, I have no idea since my flex I effed up and throwing the WB off.

[Sandman]

Tested the FP as well and it primed to 42psi and stayed at 42psi running. Pump or regulator?

[Sandman]

Also cleaned the MAF but no effect. I did a short scan going just into boost shortly, not completely WOT.

Just started a thread on 3800pro since they can host HPT scan files.

Misfire I can't figure out - 3800Pro.com Forum

[Sandman]

Hi.

[matt5112]

This may sound dumb, but humour me:

Put the shifter into the one or two position then slowly accelerate until you're around 4000 RPM then try giving it gas.

See if it smooths out up there.

[Sandman]

I'm open to anything no matter how dumb, I just tried what you said and same thing.

[matt5112]

The above is what I found when my balancer went bad.

When you replaced the wires/plugs did you do that at the same time?

[Sandman]

My balancer went out a few months back lol

[Sandman]

Checked fuses, which I should've done first, they're fine. Swapped MAP sensors and that wasn't the issue.

[matt5112]

Map doesnt do much unless the maf fails.

[Sandman]

I don't know these things lol. I've tried searching other threads but it helps when people actually report what fixed their car

[dsmuts]

How much vacuum are you pulling at idle?

[matt5112]

That won't tell you if you have a leak.

[dsmuts]

it'll tell if it's a big leak

[Sandman]

It's pulling like 20+ at idle