incubus454

I just got a 1997 Z28 that has a very rough idle and it likes to diesel (engine still runs when you turn it off) after you turn off the engine for a couple of seconds. I did an O.B.D. II test and the code came up as an EGR Flow Malfunction . I know I need to take it to a smog place and have them check it, but i just wanted to know if anyone had any ideas. Is this common?

slopokrodrigez

The EGR is a problem often because it passes burnt fuel through a relatively tiny opening. This will over time, clog with carbon and usually cause the pintle to not be able to seat. This results in exhaust gas entering the cylinders at idle when it should be closed.

If I were you, I would remove the EGR valve and replace the gasket at least. Clean as much as you can on both the intake manifold.(yeah right, it's in the back) and the EGR valve it self. If the pintle on the EGR looks ridgy(is that a word?) then try cleaning. If cleaning doesnt help then just replace it.

Also by squeezing the diaphragm in the back openings of the EGR, you can feel if the plunger that opens the pintle is rough feeling or sticking. In that case, replace the EGR.

While your there, check all the wiring and vacuum lines connected to the EGR system.

Try this first before you pay anyone. It could save you some money.