bad alternator? erratic rpm needle / rough idle -
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post #1 of 2 Old 05-22-2013, 12:42 PM Thread Starter
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Join Date: May 2013
Location: High Point
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bad alternator? erratic rpm needle / rough idle

I stopped and got gas on the way home yesterday and after I hopped back in I cranked it back up. Instantly it was running rough at idle and would sputter when I gave it gas. The RPM needle was literally bouncing around all over the gauge (almost like when you reset a cars computer and crank it up for the first time) but the engine remained idle but idling a little rough. Could this be a symptom of a failing alternator? My voltage on the gauge has always been below the 14v a little ways. It typically stays between the first line and the 14v mark but never exactly 14v even with everything off.

Since about March of this year I have put in a brand new battery in it back in March. Since then I have replaced 02 upstream, crankshaft position sensor, plugs, wires, rotor cap, ignition coil, ignition pickup, catalytic converter, muffler, exhaust manifold.

1997 Wrangler
2.5l SE

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post #2 of 2 Old 05-24-2013, 04:16 PM
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2005 LJ Wrangler 
Join Date: Feb 2011
Location: Dayton
Posts: 2,330
First clean your battery terminals and connectors. Also clean the opposite ends of your ground connections. Your description sounds like a poor resistive connection. Your battery meter should be on the high side of 14 when running and 12.6 engine off. You could use a multimeter to verify.

"Never look down on anyone unless your helping them up"- Jesse Jackson
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