Questions and Answers

Bucking Bronco Q. It was running well when suddenly it started running bad. when idling, the rpms go up and down as if it wants to turn off. I want to know if the oxygen sensors have anything to do with that. Also, how many sensors does it have? We have received various answers. I have changed the spark plugs, wires, cap and rotor, one sensor, and the EGR valve.

The engine light still comes on and the idle is rough. If you could help me solve this problem, it would be greatly appreciated.

Thanks,
Jesse

A. There are many things that could cause the condition you describe. The fact that the check engine light is on is the indication that the code for the problem has been stored in the computer. By changing parts at random there is a chance that you will, by a stroke of luck, replace the bad component. But this can be a costly method of repair, assuming it is a bad component and not a wiring problem.

The best thing to do is to bring it to a shop that has a scan tool, pull the code from the computer and check that circuit from end to end.

As for how many sensors it has, there can be up to as many as 12 major sensors directly related to engine operation and many more others relaying information to the computer.