I am having trouble with my 88 ford ranger. I have changed the plugs, wires,distributor cap, rotor button,fuel filters and the timing belt.All of these were checked by a repair station.It runs fine until it warms up. Then it starts bogging down at times and then comes out of it and runs fine for a while and then will do it again. I don't have much power up hill and am using an ungodly amount of gas.I have gone from over 20 mpg to under 10 mpg.I can also smell gas after I drive it. Got any ideas?