After going back and reading your first post, it got me thinking. This started when the engine was under load. Is the misfire on the same cylinder? Check that plug again, if problem is still there, pull the valve cover and check the valve springs, rockers, and pushrods. A few months back I had a GTX here with a bad misfire, it would come and go, ended up with 3 of us looking it over, we checked everything. Finally pulled the valve cover and found this.



This didn't even show up with a compression test.

i'd make sure your plugs are all good... did you gap them correctly? also, check that you didn't break one of the wires. i did on my alero and it would cause an intermedient misfire.

Now you that you guys mention this when I bought the plugs from AutoZone 5 of them were in a box and the 6th one was not. The gentleman selling me the plugs assured me the one not in the box was brand new and it was the last one they had, but no box. I gapped them using my gap tool so I believe I correctly changed it. What should I be looking for on the plugs to see if they're bad? Thanks again for all the help guys

If they have the screw on caps, check them like Dan suggested. Other than that, look for correct gapping and any obvious damage. Once that is done, check your wires and coils as explained in the link I sent in an early post.

You might also want to try spraying a fine mist of water with a spray bottle around the plugs, wires and coils at night, in the dark, with the car running (in park) and someone revving the engine. Look for blue sparks around any of the wires, plugs and coils as a sign of a defect.

You might also want to forego all the diagnostics and put on a new set of plug wires. If you haven't put new ones on since you got the car, and the previous owner didn't tell you he put new ones on, it would be a good investment, and it may clear up the problem. If you do put on new wires and still have a problem, come back and tell us.

Either way, let us know how you make out.

Thanks for the help. I plan on cleaning my MAF this weekend so I'll check this when I do that. I'll let you know what happens. Thanks again

I had the same thing happen after putting new plugs in, i somehow (or it was like this before) cracked the porcelain insulation and it was arcing thru the crack at WOT, not noticable but one of the techs, i work at a GM dealership, took some black grease on his finger and ran it around the insulation, a little went inside the crack and that was how we noticed it... try this and if you find something similar, replace the plug

just an easy test and my 2 cents

I had the flashing check engine light under hard acceleration. It ended up being heavy corrosion under the plug wire on the coil side. Very simple to check. I have no idea why the middle coil had corrosion while the front and rear coils were clean.

Having gone through issues with misfires twice, I read a ton of threads on the topic. There are certainly many possible sources for a misfire, but it seems the most likely suspects are plugs, wires, coils and fuel injectors. In that order.

maybe the ignition control module? i had the flashing engine light multiple miss fires ect.... changed the module and all things were fine after.