running on seven cylinders

[mazodc]

1997, GT 40, 500 hours. Starts great but after it runs for 20 minutes, it develops a cylinder miss. I have all new wires, Ohm'd out all the injectors cold and after running and all were within tolerance, also used a snap on tester to check the injectors under stress and all worked the same. You can smell the raw gas out the exhaust after it starts missing. Any help or idea's would be appreciated.

[crobi2]

How about checking the compression, check the dist cap for a crack or messed up terminal, check the wire, replace the spark plug, and say a prayer!

Good Luck

[Laketexoma]

Check valve lash. If it gets hot and doesn't alow a valve to close all the way. Just a thought.

[Jono]

Easiest one first - cap and rotor?

[Tom351]

I agree with all of the above...and if you have an IR Thermometer you can easily locate the offending cylinder...just check the temps of the exhaust manifolds right where they meet the cylinder heads...the dead cylinder should be a good bit cooler than the others...this may help track down the problem.

[charlesml3]

Most likely a hairline crack in the distributor cap. Replace the cap and rotor.

-Charles