Yesterday my blazer was suddenly idling really rough. It felt almost like a spark plug wasnt firing. However, when I really stomp the pedal all the power is there. Just cruising at lower RPM it sputters and backfires a little. I opened the hood to find fuel leaking from the fuel filter housing, and a vacuum hose had come off the carb. I put the hose back on and replaced the fuel filter and took care of the leaking and the problem is exactly the same. What could it be. Plugs and wires are new and none of the wires melted on the header. Ran fine with new plugs/wires for a week.