When I rev the engine and push on the diaphram of the EGR valve I start to see smoke coming from the rear of the engine; somewhere in the area of where the return exhaust feed is. When I release the diagphram the smoke dissipates.

From testing the egr system: I feel vacuum out of the block, I feel the pulse coming from the solenoid.

Should I try swapping the egr valve?

 

You need to tell us - as a minimum - the year of the car and the exact engine type. EGR systems are not all the same, over the 36 years of the F-Body.

 

Sorry.... It's a 94 Z28 with 215k on it. Has Edelbrock headers, cat back exhaust from a 97 SS.