Alright i have noticed some ping on my 91 deville 4.9, Timming is good, I always use premium. I know a tune up would be nice, but I'll do that in a month or so....when i can afford the good shit. So my only other place, other than fuel mixture would be in EGR function. I pulled my air cleaner adaptor off and saw the valve mounted to the intake....I did not see any tubes like I am used to seing on cars, do I just take off the valve and clean the passages under it? Whats the best way to do this, iv eused coat hangers with much success in the past.


-The Cadillac Rancher

Forget taking the EGR valve off for now.

Hold the throttle blades wide open and look down the throttle body bores with a strong flashlight. See the two tubes sticking up from the floor of the intake manifold down below the throttle blades? Those are the EGR tubes and they are not supposed to be full of carbon and such. Use your coat hanger wire on them to clean the carbon out all the way thru down to the passage below.

Also check out all vacuum hoses from the throttle body to EGR solenoid and valve. The elbows are notorious for cracks.

Sounds simple enough...