95 2500 7.4l running rough

[offroad_boy]

i just bought this truck a little over a week ago and it has 200k miles on it. it was running fine and everything until today. yesterday my dad said the check engine light came on but this morning the light was no longer on. i went ahead and check the codes and came up with three. the first said someone was wrong with the egr valve (it passed smog just last week) one said the torque converter clutch is off. and the last said said something about the timing was screwed up. anyway i cleared all the codes cuz i wasnt sure how long theyd been there and started up the truck, rev it a little and went thru the gears then scanned it again. there where no codes so i figured id drive it for a week or so then check codes again to see where i was at. anyway latter i got on the freeway and got up to around 75 or so and when i came to a stop the truck idled very rough and check engine light came on. the truck seem to do okay though when on the gas only at idle. what should i do?

[gmtech]

Check the codes again it is probably the egr valve getting stuck open which will run fin down the road just rough idle and maybe even a hard brake pedal.

[offroad_boy]

egr valve replaced and it runs great. thanks