I recently bought a 1978 Pinto 2.3L with 4-speed, no air, bare bones but not Pony. 52,00 ORIG. miles... absolutely stunning condition. Car ran OK, but no idle and backfiring on deceleration. I got home OK, and proceeded to check/replace certain things. It now has a new air pump (old one was very noisy), rebuilt carb, cleaned distributor, new wires, plugs, PCV, all vacuum hoses carefully, one-by-one replaced, fuel filter, etc. The timing belt was replaced at a Ford dealer by the previous owner. I CHECKED carefully both ignition timing AND that the cam belt was properly installed. It is spot-on correct. Timing is precise and correct to spec. When overhauling the carb I discovered the pin holding the choke linkage had come loose screwing up choke operation. I repaired it and all works perfectly. The only thing altered from original is the drop-down solenoid (anti-dieseling) was removed. When I fired it up it ran exactly as badly, unable to idle and backfiring on decel. Living in Colorado I MUST pass emissions so all that equipment needs to work. Can anybody suggest what next to check (there are a load of sensors yet to check) that might cause this condition? I did discover cylinders 2 and 3 are oily (on plugs). Possibly stuck rings or valve guide seals? Please help! Thanks,
Don