i have a 1987 s-10 2wd drive with a 2.5l 4 speed. it has a rough idle and surges when your going down the road. this is what i haven done so far. new plugs, wires, distrubtor cap, rotor button, changed oil and filter, egr gasket,air filter, fuel filter, pcv valve. what else could it be, i have look at all the vacmun hoses and couldn't see any leaks. any help would be grateful.
rodney