Intake gasket blown?? Help/Ideas??


Active Member
May 24, 2001
Need help to figure this out guys! Lets first start off by saying I pulled an 11.40 motor to drop in a mid 10 sec Weber built motor that is proven. I started out chasing down a mild miss. At idle car is fine and steady for the most part. If you put it in gear and give it a little throttle and hold it with the brakes on the car will miss and rpm will fluxuate intermittantly. The car at wot is also breaking up a bit but not real terrible but you can tell it isnt right.

So I started replacing everything with known good parts. Coil pack, module, plugs, wires, MAF, computer, chip, crank sensor, cam sensor cap, and added another large ground wire and still have the identical miss.

So I moved on to changing the throttle body with another known good one since there was basically nothing left...with the tps, iac still on it off the 11.4 motor. When I removed the throttle body I see a decent amount of oil in the intake and on the back side lid of the throttle body...the front entry side of it was dry as was the uppipe so I know it wasnt the turbo which is brand new. I am getting a slight amount of oil dripping off the driver side valve cover filter which is telling me some blow by which there should be next to none on this engine.

Should there be any oil in the intake? It is drenched inside when you look in it. I am leaning toward a intake leak of some kind due to the gasket or a crank in the intake manifold. What are your guys opinions?
Maybe you are sucking some of it through the PCV? Doesn't explain the miss though.
Yeah Im not sure if the miss is related to it but Im leaning toward it is. Need to know what would be causing the intake to have so much oil in it and how its getting there.:confused:
my friend had a late 90's dodge ram with a 360 in it, same metal cookie sheet style intake gasket/valley pan. dodge actually had a bulletin for it leaking around the intake ports causing his intake manifold to get covered in oil, causing some misfires and pinging during highway cruise.

the oil coming out of the breather could be due to the same leak just when under boost the air is pushed into the lifter valley and out the breather, instead of oil being sucked into the manifold.
Just pull the intake and see if/where it's blown. The manifold to head alignment is critical, and if the heads have been milled and/or the use of thinner head gaskets, then there WILL be a misalignment. As stated before, check the PCV valve for oil being sucked into the plenum. If you are using a Fel-Pro 1200 intake gasket (non valley pan style) then you will not be able to run a PCV valve, at least not in stock configuration. Do a leak down test to see if a head gasket is hurt, also.