Last week after driving my 91TPI TA for about an hour, the SES light came on. I checked it out, and it geve me the EGR system code. ANy ideas what I should check first to see what is wrong? Secondly, there is a buzzing sound coming from the engine, it sounds like its from the back, or middle of the plenum, most noteably heard on the passenger side. I can't tell if its distributer, electrical, or maybe EGR, given that I got that code. It seems to only buzz when up to normal operating temp. Just thought I'd see if anyone might have a shot in the dark answer to my buzzing problem. I know its kinda vague, bu I thought I'd try. THanks

I'd suggest a close inspection of the EGR solenoid, its wiring, and the grounds. That may solve both the noise and error code.

i've had ignition coils that "buzzed" before.

I guess that buzzing/noise could be from a blown EGR diaphragm.

Good point. If you were to catch the noise when the EGR solenoid was modulating vacuum to the valve, AND the valve pilot was closed, a perforated or torn EGR main diaphragm might buzz. Of course, none of that should happen at idle.

Thanks guys, I figured someone would have some good idears. I'll check it out and let you know what I found.