oil in the air filter

I have a 1992 Bronco with a EFI 302. A few months ago I noticed the engine started blowing oil into the air box and the truck lost a lot of power. i figured out there was a lot of backpressure and had the cats checked out, they were fine. Then I found out the muffler was clogged and I replaced with a glasspack muffler. Almost all of the truck's power came back, but it is still blowing oil into the air box (although not nearly as much oil as before). I checked the compression and the numbers were almost as high as when it was new. I also replaced the pcv valve twice thinking that was the problem, but it wasn't.

Please help, I can't find any info on why the motor is doing this.

Thanks

Quote:

I have a 1992 Bronco with a EFI 302. A few months ago I noticed the engine started blowing oil into the air box and the truck lost a lot of power. i figured out there was a lot of backpressure and had the cats checked out, they were fine. Then I found out the muffler was clogged and I replaced with a glasspack muffler. Almost all of the truck's power came back, but it is still blowing oil into the air box (although not nearly as much oil as before). I checked the compression and the numbers were almost as high as when it was new. I also replaced the pcv valve twice thinking that was the problem, but it wasn't. Please help, I can't find any info on why the motor is doing this. Thanks

Did you try pulling the valve covers off and replacing the valve seals.
you maybe getting blow by and though the pvc valve back up into the intake.
Also how many miles on this motor, may need to put brass valve guides in, they wear on the ford heads.

Hope this helps

Thanks for the help, my motor has 99,000 miles on it.

I read on another web site that the valve guides could have wore down and be the problem, but wouldn't that lead to the engine having bad compression? When I did a compression check, the numbers for each cylinder were only 5 psi apart from highest to lowest.

did you check the pvc valve?

Yes, I checked the PCV valve and replaced it twice. Thanks for the help so far, keep posting.

did you check your air filter to make sure is was'nt saturated in oil if it is the oil will get sucked into the intake