Enginer idles rough after warm up

[krp33]

I have an 86 chevy custom deluxe with a 305 and 700R4. it also has dual exhaust with dual cats. the engine is in pretty good shape, usually runs really well, and does not burn any oil. Lately I have been having a problem with it. When I first start it it runs great, but after it fully warms up and i drive it for a while it will idle really rough at idle and almost stall. The drivers side exhaust also smells like charcoal. Once it cools off it runs ok until its hot again. I found a vacuum leak at the egr gasket and fixed it, but it still idles rough when hot. any ideas would be greatly appreciated. I was thinking that maby the charcoal canister has failed, but I haven't had a chance to look into it yet.

[diphthong]

Charcoal not an egg small, correct?

[krp33]

yes. Charcoal smell, not an egg or sulfer smell like a cat would produce. it's very wierd. it'll get to where you can smell it from the cab.

[Irish_Alley]

kind of a stretch but never heard or smelt it before so i searched yahoo for "smell charcoal" are you the only one who smells it? if so
http://www.netwellness.uc.edu/question.cfm/66558.htm

[VileZambonie]

disconnect the EGR valve and ensure the valve isn't sticking open.

[diphthong]

If you can stand outside of the truck when it starts to die try spraying some starting fluid into the intake.  If it smooth out, you'll know it's lean.  If it seems to die fast, it probably indicates it fat (rich.) 

[klaussk]

sounds to me like ur carb needs a tune and cleaning.

[krp33]

problem solved. the intake manifold gasket was blown around the exhaust crossover on both sides and leaking exhaust into the intake runners of cylinders 5 and 6.

[Irish_Alley]

what made you look there?

[krp33]

the idle would pick up when I squirted carb cleaner around the egr, which I just replaced, so I knew it was good, and had good gaskets. It would also pick up around the exhaust crossover on the other side. I checked the all the bolts and the 4 center oned were all very loose. When I tightened them up the engine smoothed out. When I pulled the intake I could see where the gasket was blown out on both sides. Sometimes you just gotta get in there and check it out.

[Irish_Alley]

cool nice find