What makes a 98 expedition backfire?

Answer 1

Causes for backfiring normally wont change from one car make to another, backfiring in a nutshell: A backfire is when the ignition of fuel doesn't take place in the ignition/combustion chamber, it(a backfire) can take place in the intake or exhaust. It can be caused by a fuel to air ratio not being correct, also if the timing of the spark is not just right that could cause it to back fire. It could be running lean with not enough fuel and too much air, or could have too much fuel and not enough air. It could be because the intake valves are not shut when the combustion takes place, therefore the combustion would take place in the wrong spot. The most likely cause are from: 1. Incorrect timing, the timing issue could be caused by bad wiring/ or bad ignition. 2. Incorrect fuel to air ratio, bad fuel filter, low fuel pressure-caused by weak fuel pump. Most cars will have the same cause for backfiring, as long as it's an internal combustion engine it shouldn't differ...