Engine backfiring and wont pull itself

The first step is to have the diagnostic fault codes read and recorded. Many auto parts stores will do that for you for free, but remember, they're in the business of selling parts. Fault codes never say to replace parts or that they're bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a part is referenced in a fault code, it could be defective, but about half of the time the cause is something else like corroded connector terminals, cut wires, and things like that.

Popular misconception. The Check Engine light has absolutely nothing to do with reading fault codes. There are well over 2000 potential fault codes. Only those related to something that could possibly have an adverse affect on emissions are required to turn the Check Engine light on. About half of the codes never turn the light on. Many people think there are codes in the computer only when the light is on, but in fact, fault codes stay in memory even when the light was on and goes off. The fact the light goes off at times indicates whatever problem was detected is relatively minor, at least as far as emissions is concerned.

Fault codes can be erased with a scanner or by disconnecting the battery, so it is important to not disconnect it or let it run dead until those codes have been read and recorded, otherwise that valuable information will be lost.