i have a 97 4.3 4wd 93k, it has a stumble sometimes i hit the gas and it almost dies or when im sitting at a red light sometimes the idle will drop almost like the iddle needs adj, i just put a complete tune up and a new battery, i checked the fuel psi at idle and it was around 60 psi, ive tried dry gas,fuel inj cleaner and now i need help, no check engine engine light comes on or nothing. thanks .