Hello, I have a 94 k5 blazer with the 5.7l 350 in it and automatic transmission. It is idling really low when in drive and idles really rough sometimes when stopped at a red light. Like it will idle really rough and shake the car, then smooth out and then idle rough again. Also sometimes when I go to accelerate from a dead stop it hesitates and almost dies and then picks up and goes. Check engine light is not on, replaced the spark plugs and did an oil change last week. HELP PLEASE! (: