I have a 90 teg ls and a few days ago I was was driving down the road and wham the car started skipping and chugging along real bad. So I went to autozone and replaced the plugs and wires and it didn't help.The next day I went and bought a new cap and rotor button along with an ignition coil hoping to solve the problem but it didn't do any good.The car idles real rough sitting still and the tailpipe seems as if its trying to spit the exhaust out.I took it to some shops and they seem to think I may have blew a head gasket around the middle 2 cylinders because when you pull the wires off of the middle 2 plugs the car does not cut off but if you pull the wires on the 2 outside plugs the car will immediately cut off which they say means the middle 2 cylinders are not firing.Are the y correct or culd maybe my timing has jumped and is causing this problem. Any suggestions would be gladly appreciated. Thanks.