moriise

I have a 1996 with a 396cui Golen engine.My truble is wery sooty sparkplugs on nr 5,7,8.When i pulled off my intakmanifold it was a lot og oil in the intakrunners.I have deleted egr and pvc on the manifold so no oil comes in here.When i connect my hp tuner i can see the pcm is adding 25% fuel. What can this problem be.
Morten
NORWAY

C4fan

I'm not a pro but I was reading a post with a similar problem where a blown intake gasket was discovered allowing oil to come in via the lifter valley. It seems to me it was on a 383 engine and may have been ported heads/intake leaving thinner gaskets. I can't remember the post or I would send a link. I think they talked about a way to test for the leak also. That may be something to look into but I wouldn't go taking anything apart just yet.

cv67

You need some kind of pcv system on the car do you have them on the valve covers at least?

cumbercr

I had the same symptoms from a bad intake gasket. The gasket was deformed around the intake port on #7 alloying oil to be ingested from the lifter galley. It also caused a vacuum leak that was read by the O2 sensor as a lean condition.

mseven

MO, the oil could be blow by from unseated rings, or bad gasket sealing and the sooty plugs from lack of tuning.