OK. That is where you need to start. You must pull codes to get an idea what is going on with your engine. Once you have any available codes, I can get you the test routine(s) for the code(s). Your Bronco II is controlled by an old EEC-IV (also referred to as "OBD-1") computer system. Many of the younger techs have no idea what to do with one of these systems because they cannot use their OBD-2 code readers on them.
You can get codes out of that system using an analog volt meter (the kind with a meter/needle) if you have one of these, I can tell you how to do it, but the instructions may be a bit hard to understand unless you have done this before. If you do not have an analog volt meter, there is a very nice OBD-1 scan tool that will work very nicely and it is pretty cheap (lots cheaper than an hour's worth of diagnostic time at most shops). It come with full instructions on how to pull and read codes. You can check that out HERE.
Please note that a digital multimeter will not work for reading codes...you will just get numbers running all over the place.
Let me know how you want to do this. If you decide to get the scan tool, come back and post the codes you get and I will walk you through the actual diagnostics.
OK cool! The scanner will make life a little easier. Do the instructions with the scanner explain about Key-On-Engine-Off (KOEO), Key-On-Engine Running (KOER) and Continuous Memory self-tests? If not, let me know, and I will send some information on this.
I have uploaded a list of service codes for your vehicle. Please note that code 67 is listed twice. That is because it be retrieved either in KOEO or Continuous Memory. It makes a difference what it means, depending on which part of the system it was stored in. Usually when this code appears, it means that your air conditioning controls were not in the OFF position when you tried to run the KOEO self test. Make sure the controls are off and try it again.
You can download the list of service codes HERE
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