95 Suburban, intermittant rough idle

Any codes? Sounds like a dirty EGR valve. It's a big mushroom-looking thing. It allows a small amount of exhaust gas into the combustion chamber at high speeds to reduce combustion temp to manage NOx's. When it gets stuck open, it allows exhaust into the chambers at all times and can cause a rough idle. You can either buy a new one or clean your existing one. If you remove yours you can plug the hole, to CHECK if it solves the rough idle. Do NOT just plug it.

GMC Gremlin

pull the vacuum hose off of the EGR valve and stick your finger over it. if at idle you feel vacuum, replace the solenoid as it's leaking. if not, plug the EGR valve end of the vac line into the vent ( this will prevent weird vaccum leak symptoms for the following test.) and drive the truck around. if it's better it's the valve, if it' not better look else where. you can pull the valve and clean it with brake cleaner... I'd try that before dropping 80 bucks on a new one.

hth, Bret

Sounds like your FPR (fuel pressure regulator) is on it's way out and causing it to load up when you're idling and causing the rough starts. The other folks who suggested EGR might be correct, but having to crack the throttle to start it isn't a symptom of a crapped out EGR.

Doc

thank you for the replies guys. i have no codes because i do not know how to get them. is there a scanner or something that i need to retrieve the codes? abd

IIRC it's either 95 or 96 that they still had the OBD I system with the OBD II connector, so you need a shop-quality scan tool, bout $2,000.

GMC Gremlin