spark plugs was changed not more that 10 K miles ago..

the set before that lasted 15K miles..

all of the sparkplugs stays in good condicion exept!! the ones from cylinder 4and 8 the ones closest to the firewall.. i was told that the PCV valve is bad but it was replaced 5 K ago... the 4 and 8 cylinder spark plugs comes out OILY! and i guess the oil wont let it spark correctly

another thing... how to chek while engine running wich plug is bad? remove the wire at the dist. cap one by one and see wich one is it? or remove it by the plug? wich way wont give you a shock ? lol

i just want to know wich one is bad and replace it with one from the old set wich is good and see if it corects the problem.. dont worry its the same type sparkplug the old and the current set they dont have more than 20K on them

they are motorcraft platinuims

You can pull the wire off the plug.

Don't use platinums. Plain old autolite copper plugs are the best. For some reason these older Fords don't like platinum plugs. That's not the reason your plugs are fouling, but you just shouldn't use them.

I know on the 302, the PCV valve dumps right into the #8 cylinder, causing it to run lean. I'm not 100% sure where the PCV line goes to on the 351. If it's sucking oil for some reason, that could be where it's coming from.

The other possibility is the rings. How is the compression?

dunno never did a compression chek but the truck has enough power to ehmm enough lol.. still enough power on 7 cylinders.. lol

yeah i have a brand new set of autolite coppers gapped 0.55 waiting to be installed when these platinuims go bad.. i guess its time..
but they are not so old.. thats why i made this thread i have to change plugs every 10 to 15 K miles.. and its always the 8 and 4 plugs that comes out oily..

I had a fouled plug once due to it being loose. Are they completely torqued down when you're removing them, or are they spinning out?

Ryan