My 95 1/2 ton silverado with 5.7L is running rough, and I can't find the problem. =A0=A0It acts as if it is going to stall when I accelerate and begin to slow down. Once I stop, it idles good. The check engine light doesn't come on. I replaced the fuel filter, air filter, distributor cap & rotor, and ran 2 bottles of fuel injector cleaner thru the system. I also cleaned the idle control valve. None of these things helped. =A0=A0When the truck sits for several hours, like overnight, it doesn't begin acting up immediately, only after a few minutes of driving. Any ideas on what could be wrong??