I have a 1992 Chevrolet S-10 pickup that will crank right up but once it is started it idles up and down then cuts off if I don't give it gas. Once the truck is put in gear it idles extremely low and then cuts off if I don't give it gas, however when I give it gas it stutters and stalls out and sometimes backfires through the throttle body. When going down the road the truck jerks and when giving it gas it bogs down and if I floor it it will bog down then take off wide open and revs really high before changing gears. Any help with this would be greatly appreciated