2006 Buick LaCrosse misfire - Replaced coil pack, new plugs, new wires, 2x junkyard ICM. Still no luck

I have a 2006 Buick LaCrosse 3.8L that is misfiring. There is a strong smell of gas when running.

I have had this issue before and it was solved by replacing the ignition control module. I also replaced the plugs, wires, and coil pack while I was at it.

This time, replacing the ICM twice had no effect. I also replaced the coil pack a second time. Still nothing. I have an inline spark tester and it lit up on every cylinder when put between the coil tower and plug wire.

I have a bluetooth ODB reader, a multimeter, and the aforementioned spark tester. I am getting code P0300.

Tests I have run:

• Spark test with inline tester, all OK.
• Spark test by looking for sparking at the coil towers, all OK.
• Removed plug heat shields. No change.
• Unplugged MAF. No change in engine running, maybe that’s it? I didn’t run it very long with the MAF unplugged though.
• Checked battery. OK.

Tests to run:

• Cylinder by cylinder injector check.
• Compression test
• Fuel rail valve test.
• Smoke test
• Check brake booster.
• Check PCV valve.
• Check vacuum line. I did see one going from the top of the engine to the intake and I didn’t see anything obviously wrong with it.

I would also like to add that before this happened, I had issues with the car RPM fluctuating under heavy load. You could hear the RPM fluctuating and the car lurching.

I would also ask that you take a look at the spark plugs I got just in case they’re the wrong ones.