EGR code, service engine soon light ,just can't get it fixed.

[hossfly]

my service engine soon light comes on, the code reads EGR problems and my machinac said it was probly stopped up with carbon, he cleaned it and replaced the gasket and checked vacuum and it all checks fine in his shop but after a few days the service engine soon light is back on again and still reads as egr code. the engine runs as good as it did 134,000 miles ago when I bought this 97 monte carlo V6. I have always gotten 31/32 mpg on the highway but now, with the service engine soon light coming on , it has dropped to 21-26 mpg highway. what could be the problem with this thing. considered the catalic convertor but like tI said , the engine just runs too good. no loss of power or acceloration at all.really got us stumped and I'm sure he is getting as tired of having me bring it back to him as I am of taking it in,LOL.. I'm on a very restricted budget and can't afford to sink $200-$300 in it just to try something new. any ideas out there from those who might know? thanks. getting really frustrated here.

[tom3]

I believe these have a three element electronic EGR valve. Big money there. If the valve was actually carbonned up and dirty, you'd probably have felt it in the idle, really makes it shake, miss, and stink usually. I'd guess a bad valve, but if I'm wrong that's some serious money thrown away. Hate to say it, but a dealer with the high tech test equipment could pinpoint the problem and get it right. Might be cheaper to tape the light and buy the extra gas for several years though. Tough situation.