I recently put dual exhaust on my bronco and now my engine idles up to 1500-2000 rpm by itself. I have put a new oxygen sensor in and other sensors that deal with the exhaust and throttle body but I still have the problem. do you have any ideas?
by Visitor in Arcadia, FL on March 18, 2010
I have to assume that this was not happening prior to the exhaust work.The two most likely problems are an unmetered air leak, like intake manifold plenum gasket, cracked vacuum hoses or the wrong PCV valve. If you hear a lot of hissing in the area of the PCV valve you may have the wrong one, get a Motorcraft one and try it, that is the cheapest and easiest thing to try. The other thing could be the the throttle body, since you replaced that. Was this a new or used part?On the throttle body is a valve with a two wire connector, the valve is cylindrical with a flat base and two bolts holding it in place. If you unplug this valve with the motor running and the valve is functioning properly, the engine should slow down. These valves can get stuck and make the idle stay high. These are your first things to check, let me know the results and I can try to help you further. Good luck.