Misfire after head gasket change

LEXY COVATTA

MEMBER
1997 PONTIAC SUNFIRE
153 MILES

My husband car is listed above with a 2.2 automatic. We bought I from a used car lot recently ran and drove just fine until recently when he discovered oil in mixed with anti freeze. This is his third Sunfire he loves them he has one custom and this daily, he knows how to work on them with his eyes closed. Knowing he needed a new head gasket he went in and changed it out. We knew that there was a misfire before this issue and he went and got new spark plugs and replaced them. The check engine light was still on so he figured it was from the gasket. Well after the change and put back together it is misfiring really bad in cylinder four. Spark plugs are brand new. He has tried everything he can think of and nothing is helping. He is very aggravated and upset due to the fact this car is what he needs to be able to do his job. Needs fixed ASAP. Help?

1 Reply

STEVE W.

MECHANIC
13,443 POSTS

Misfires can be a pain. First thing to check is spark. Swap the wires on one and four, as this is a waste spark system that fires one and four off the same coil, and number one appears to be firing the plug wire is suspect. If you swap them and number one starts misfiring you have a bad wire. Next check the injectors, they can short out and not operate properly, Here you could just swap three and four, if the miss moves to three you have a bad injector.
If these do not help, do a compression check to help rule out a problem in the lower end. Fuel pressure check as well as making sure the regulator is okay would be a good thing as well.