Trooper won't start
 

I have a 93 3.2 SOHC and replaced the starter. Before replacing exhaust pipe I hooked up the battery to check starter. I did not crank it long enough to start but got a small backfire. I buttoned everything up and now truck will start after sitting awhile but will only run for a second. I replaced fuel filter,checked fuel pump,fuses and relay. I also sprayed O2 sensor connection with electrical cleaner because it was coated with oil and grime. Any help would be GREAT. THANKS

I dont know whats going on but I jsut wanted to tell you if you pull the starter off again you dont have to remove the exhaust, after struggling for hours with my 94 i foudn that if you take the valve off the shaft and flip the starter over sideways and backwards it slides right out, sounds complicated but if you look at it youll see.