1990 GMC Safari engine problems

http://a.tribalfusion.com/i.ad?site=AutomotiveForumscom&adSpace=CustomCampaign&size=300x250&requestID=1416317259 (http://a.tribalfusion.com/i.click?site=AutomotiveForumscom&adSpace=CustomCampaign&size=300x250&requestID=1416317259)I have a 1990 GMC Safari with 4.3L TBI engine. Engine runs/idles very rough, I have changed/subbed all emission parts including ECU. All vacuum lines and cylinder compression are good. Complete tune up and rebuilt TBI, nothing seems to fix the rough idle problem. Any suggestions will be appreciated.

did you try taking off the egr valve and cleaning it and putting it back on, alot of times carbon builds in it and causes those problems.

I second a good egr valve cleaning. take it off and SOAK it in carb cleaner. I used a tiny brass brush and cleaned out all I could. You'll feel the valve start to get nice and free when your getting there. I wd40'd mine then, but that may not have helped or been nec. It worked though:)