I have a 120,000 mile 92 xj 4x4 with a 4.0 aw4 231. I have a phantom studer about once a month but usually i just floor it and it clears up. Then last month i went from 14 mpg to 10 mpg did tune up plugs, wires, cap, rotor, coil, map sensor, air filter, and oil change. That got me back to 14 mpg and running grate. so this morning fire up the jeep pull around the corner from the house jeep studers and dies. won't crank up so i pushed it home got the wife to run me to work. This afternoon i get home jeep cranks up and is studering floor it and it clears up. Now it's running fine but my alternator gauge was at 9 instead of its normal 14. Was thinking it was my cps this morning maybe my ecu but the alternator thing has me even more confused please help.

 

Concentrate on the 9 volts you are seeing on your dash gauge.

Odds are high that your alternator has failed.

Any parts store will bench test your alternator for you for free. While not 100% conclusive, it catches many of the failure modes. I'd recommend it.

You must get a solid electrical system before trying to troubleshoot any other issues.

 

Thanks tj will do. Also I'm thinking of doing the Dakota 2.5 117amp alternator swap but need to know what year too get. 3 hrs of Google and still have not found the answer anyone have that answer?

 

So any other ideas?

 

o2's and TPS ground at the clock spring.