i've got an 88 s10 2.8l v6, and it runs like a dream except for a small problem. first of all, i have hesitation accelerating from stoplights. also, when the truck is warmed up, it's hard to start it up - i have to press the throttle to make it start. after i get it started it stumbles for a moment and then idles fine. i've used winaldl to take a look at what's going on - when the idle smooths out seems to be when the iac opens itself more. also, at idle (and ONLY at idle) the oxygen sensor reads 0.99 (rich). sounds like an egr problem to me, but i replaced the valve with no effect. i then tried capping the vacuum before the egr solenoid (completely disabling the egr) and no luck there either. i don't have much faith in my aftermarket replacement - is there a way that it could be allowing exhaust gasses in without any vacuum? what could be some other causes?
Morris