94 GT oil fouled plug

[PickupMan]

Ok here's what I got. I purchased this GT last year and put new plugs in it. One of the plugs, can't remember which one, is oil fouled. It might be number 8 but I think it's 7??? Anyway i did some searching and read where if it's number 4 or 8 plug fouled try a new PCV valve. My guess is the intake is sucking oil in from the valley and was going to replace it but is there any checks I can do to varify the intake is sucking oil?

Thanks

 

[Zero Signal]

Well, our PCV setup is known for sucking oil into the intake. There are relatively inexpensive oil-catching kits out there. But, I could do a compression and leakdown test first. See how the numbers look and try to rule out a problem with the bottom end. How many miles are on the motor? Depending on the condition of the engine, the valve guides may be worn and the seals may be leaking.

 

[PickupMan]

I did happen to do a compression check on the engine prior to purchasing it and all the cylinders were dead even...or dam close. I was thinking valve guide seal too but it does have a funny idle...almost lile it has a cam in it. This is what made me think it might be the intake leaking. The car has 108,000 miles when I parked it for the winter.

 

[Zero Signal]

Well, a good test of that would be to remove the upper intake and inspect the runners for oil. If the runner feeding the cylinder with the bad plug is black/oily, you may have your culprit. It doesn't completely rule out everything else though. If you have blow by causing excessive crankcase pressure, it may be spitting excess oil through the PCV. If the motor runs well, I would probably just bandaid that issue with an oil catch in the PCV line.

The funny idle might be an electronic issue, so start checking things like the IAC and the TPS.