Had an oil change and a radiator flush done, a week later it started hesitating when I step on the gas, has a hard time accelerating very sluggish. The check engine light came on with the cruise light flashing (I don't ever use the cruise), now that light has gone off but it is sluggish upon accelerating, does fairly well at higher speeds, just acting like it doesn't want to accelerate well at lower speeds such as at a stop sign or traffic light, some pinging or metal rubbing against metal sounds as well, loses acceleration when going uphill. No check engine light comes on! Someone mentioned a map sensor or possibly a misfire (spark plugs and wires). Please help me!!!! This problem is now constant!