[Toyotafanatic]

Yea, for some reason mustangs had electrical problems, It drives me crazy! but i'll try those things tonight.

Originally Posted by suprasforlife

Sounds like you have a major short. Make sure all the grounds are hooked up and not broke, sounds like the short is in the heating and/or ac system. Does it run ok if the heat and ac is off? Lagging when floored is usually a fuel issue, check the fuel filter make sure its clean, check fuel pump if needed, pressure regulator(s), injectors etc. Does it have the stock stereo in it? If not could be a bad install, if its not stock maybe check behind the stereo and make sure the wires back there did not get cut or pinched or something. Another thing you can do is check the alternator, start the car, remove the positive cable from the battery and if it stays running you know the alt is good, if it dies your alt is crap. Only keep the pos cable off for a few seconds, not good for the alt for it to be off long, about 3 seconds will let you know because it will die right away. Make sure that your ac system is charged right to. The high reving could be from a sensor, check the heat ones first. O2 next. Not sure this helps any but I owned a mustang about 12 years ago and it was an electrical nightmare, did not keep it long.