Another random mis-fire. ok when warm

[SF-Rockster]

So the story is that my car has been getting misfire codes for cylinder 4 and now also cylinder 2.
I swapped plugs around no change.
Spark plugs swapped around still no change.
This happens when I don't drive the car for a few days.
After warming up the engine it drives fine.
Checked compressions and it's 150psi.
Is the compression okay?
Fuel delivery problem?
I also have an aftermarket amp (Phoenix Gold 5 channels)that powers the speakers and sub.
Also have a CAP hooked up as well.
Would a low battery cause this too?
CEL flashes and stays solid. Check codes and it shows misfire cylinder 2 and 4 and random misfire.

Hope you guys can help.

Thanks in advance

[Steve Tinker]

Did you inspect the coil packs when you removed them to access the plugs?
Look for small cracks and corrosion - once moisture penetrates the electrical windings of the coil packs, the voltage tracks to ground causing the missfire.....

[SF-Rockster]

Originally Posted by Steve Tinker

Did you inspect the coil packs when you removed them to access the plugs?
Look for small cracks and corrosion - once moisture penetrates the electrical windings of the coil packs, the voltage tracks to ground causing the missfire.....

I swapped plugs with other cylinders that were working and also the Coil Packs as well.

[SF-Rockster]

Anyone gone through this?

[SF-Rockster]

So Still having this problem and don't know what else to do next besides test the injectors and fuel pressure.
Any other advice?

[Cloudsurfer]

If you haven't yet replaced any of the coil packs, that's where I'd start. Given the age of your car, I'd just replace all of them, but if you want to start with just a few, replace the ones on whichever cylinders are giving you misfires.

You don't know if they ever got wet with oil (from leaking spark plug tubes) previously, or are just old and on their way out. If the insulator end of the coil pack gets even the slightest bit damaged, they will cause misfires.

Also, any moisture between the wiring harness weatherpack plugs and the coil pack can cause issues.

[SF-Rockster]

Originally Posted by Cloudsurfer

If you haven't yet replaced any of the coil packs, that's where I'd start. Given the age of your car, I'd just replace all of them, but if you want to start with just a few, replace the ones on whichever cylinders are giving you misfires.

You don't know if they ever got wet with oil (from leaking spark plug tubes) previously, or are just old and on their way out. If the insulator end of the coil pack gets even the slightest bit damaged, they will cause misfires.

Also, any moisture between the wiring harness weatherpack plugs and the coil pack can cause issues.

Looks like the gremlin is gone.
After I replaced thefuel filter, put in injector cleaner and filled up the tank.
I drove around still with the misfire.
after 10 miles the problem has gone away so far.
Even sitting over night the problem has not come back as of yet.

Thank you for all your help and advice!