So I have a random miss. The first time I pulled the plugs cylinder 6 was fouled.I replaced and the car ran smooth. Maybe 2 hours of drive time go by car is parked running fine. One week later the miss is back. Pulll number 6 first and the plug looks good except for a drop of oil on the thing you move to gap the plugs. all other plugs seem normal. One thing though they all come out with oily threads and they spin out easy is that normal? I am using number 25 autolite. Stock 302 from a 91 t-bird. shorty headers.

Thanks!

Russ

 

well oily threads meains you have a valve cover leaking oil on the plugs and that cylendar could have a bad valve seal or bad ring so your getting oil in the cylendar

 

yup, and the oily plug is most likely a cracked/broken/hard as a rock valve seal.

 

I had one do that and just recently when I had a head off..I found that a valve seal had slide up on to the stem[&:]

 

yeah man once they get hard the are useless. im not positive, but it sure seems like ford and chevy were both using nitrile seals which suck. poly-acyrilic or viton ftw

 

Thanks Guys. Not the best news. So now the descion will be rebuild or crate engine.