I am having a problem with my 92 Gmc K1500 350cid, maybe someone has run across this? For some reason the EGR valve is opening eraticly, causing a rough running condition, intermitantly. It would usually do it on the third start of the day, happening imediatly.I pulled off the vacuum hose and capped it off, but that puts on the engine light. I removed the EGR, and found that the pintle was not sealing. I replaced it with a good used one , ran great for the first two starts, the back to the same problem. Then I swapped out the EGR solenoid from another working truck. My truck ran even worse on intial startup, other truck ran fine. Could this be an ECM problem? I don't understand how the EGR solenoid made it worse? Any help is appreciated!!