Misfire

[2coolit]

About a week ago I did a tune up cause i was getting random misfire every now and then. Right after the tune up Cylinder #4 was misfiring like crazy, swapped the spark plug with #2; still number 4. Replaced old wire, and still number 4. So I put the new wire back on because i didnt have the time to mess with it and i had places to go. Later that day i noticed my engine was running fine, so i figured it had some carbon build up or something and finally got rid of it. This last weekend i went on a long road trip and it was running fine until i took a rest stop and shut it off. When i restarted it it, i could feel it had a misfire. When i got on the interstate and gave it gas it was misfire like crazy. It threw a code and i had my code reader with so I quicky read the code and it was random misfire. It was very noticable, then a few hours later took another rest stop and then it worked fine again.
So you guys have any ideas?

[Fivefingerdeathpunch]

What brand of spark plugs?


And have you tried switching a coil pack around to see if the misfire moves cylinders??

Also the ICM under the coil packs could be faulty.

[2coolit]

AC Delco iridium

[2coolit]

No i havent, cuz after number four cleared up its just been random misfire so no specific cylinder. how would one check the ICM?

[Fivefingerdeathpunch]

Some parts store have ICM testing machines, but it can test good and still be bad as the problem isnt there 100% of the time.

If you could or knew anyone else with a 3800, it's easier to swap ICM between cars and go drive it and see if the problem continues.

[2coolit]

Well sometimes it works perfectly so it would probably be during that time that it would work perfectly. I know alot of people with a 3800 but none are my good friends. if all else fails i may just buy new coil packs and icm.

[Scottydoggs]

cheaper to grab one from a junk yard.