4.6L (1996-2004 Modular) MustangTechnical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within. Sponsored by Cruizin Concepts
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ok i have a 2000 mustang gt so i noticed one day my car had a little hesitation so i changed oil n plugs and coolant flush you know normal maintaince stuff previous plugs only had about 25k on them. anyways i went to autozone and got the motorcraft platinum oem plugs they said and put them in. got in car and seem to run fine and then after it got to running temp and was driven for a while the car started to miss like i floored it on interstate and the stuck at 5000 rpm and was just misfiring really bad and wouldnt pick up speed or go past 5k rpm so i thought ok maybe i got bad plugs bought new ones again and new boots and reinstalled and same thing! seems to run fine just when the car gets hot it misfires and the part that really drives me nuts is that there in no engine light! please help im going crazy another issue ive found is well its been about 95 degrees out and 115ish with heat index and when the car is stitting idling with a/c on it starts to overheat and the a/c blows warm and when u drive after a few min the temp starts going back down and the a/c blows cold again any ideas on that as well? thank you
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Did you set the plug gap? It should be 0.052" to 0.056".
Were the COP boots in good condition, I.e. not hardened, cracked, or "burnt" smelling?
As to the AC, it sounds as though the refrigerant charge may be low.
The overheating could be that the engine cooling fan is not running as it should, that the radiator is partially clogged, or any of a number of other issues that really cannot be diagnosed remotely. If you are not experienced in cooling system diagnosis and repair take it to a local radiator shop and have then check it out.
You need to scan for any pending trouble codes, and check the crank and cam position sensors.
The crank sensor resistance (Key off, harness connected) should be between 300Ω and 800Ω. The cam position sensor cannot be as easily tested--just swap it out for a new one, they are only $20 or so at the FLAPS.
Also, failing and electrically "noisy" generators have been known to mess with the crank sensor signal--have the the generator load tested...
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