Please help! My 1995 Z28 is running terribly. Misfires, extreme loss of power at all speeds, acts as though it's choking, and their is oil in my throttle body before the butterfly flaps(I guess that's what they are called) anyway what could possibly be causing oil to be pushed up into the throttle body?:

 

check intake elbow, inspect for tears to where it clamps onto the throttle body. It may be the cause of the dirty 'butterfly flaps'. Not necessarily oil, just dirt, gunk and stuff. Also, may have to too much crank case pressure (causing low compression) and thus too much fumes through the pcv valve. How many miles on your Z28??

 

I agree with BoogieZ28. I had blow by on mine that gummed up my IAC valve causing poor idle. It's easy enough to take off the T/B and clean that valve. Hope this helps.

 

The oil is coming from the PCV vent system. The line on the side of the throttle body normally supplies air to the valve cover, to be pulled through the engine by the PCV valve. If you spend a lot of time at WOT, your PCV valve is plugged, or you have excessive ring blowby, the flow in the vent line reverses, and entrained oil drops end up in the top of the throttle body, and then drip down into the area in front of the throttle blades. Check your PCV valve. Shake it, should rattle. Look for heavy oil in the top of the TB or in the hose. If its real wet, let the engine idle, remove the oil fill cap and feel/listen for a "chuffing" sound or air actually puffing out of the fill, indicating excessive blowby.

Some people have bought a Deutsch filter that replaces the elbow in the valve cover, and will help reduce oil flow to the TB.

 

i agree with above...replace the pcv, it's only 4 bucks. also, spray a SENSOR SAFE carb or tb cleaner in there and get the gunk out. you may get a little black smoke and rough idle for a few seconds but that's normal with the spray in the intake. clean the elbow, airbox, tb, pcv hose, and if it's dirty, the MAF. but only clean the maf with approved electronics cleaner, not carb or tb cleaner.

 

Thanks for the input my Z28 has 109,000 miles and counting.

 

I replaced my pcv valve about 4 months ago because it was bad. That was one of the first things I checked after discovering the puddles of oil at the opening of the throttle body and the pcv valve is operating as it should. Someone suggested that backfire would cause oil to be at the throttle body, is that a possibility?

 

Its from your fresh air hose. I capped off my fresh air hose, put a breather on each valve cover, and put a catch can inline with the pcv valve. This way I get no oil in the intake, no huffing out of the breathers while driving around town, and still get the benifits of the pcv system keeping the oil clean.