Yes, the computer doesn't like low voltage and will lose idle settings.
'95 XJ country edition, 4" coils/3/4" spacers, HD leafs with extra main added in, Ironman adjustable control arms, rough country shackles, aussie locker, JK rubicon shocks, 35" mudder's, soft 8's, cobra cb
Sold '00 TJ, 4" lift, rusty's adjustable control arms, skyjacker shocks, rock krawler adj. trac-bar,rugged ridge SYE and RE driveshaft, soft 8's, 35" mud king xt's,XJ HP D30 w/aussie locker, 4:88 yukon gears, hella 500's, rock crusher diff covers
4. 04 Dodge ram 1500 quadcab, yes, it has a hemi.
5. '08 BMW X3, Mods in progress.
I say yes. last week My bat went bad, rough idle, died at traffic lights, low cranking power. Put new batt in, problem fixxed!
it runs fine above idle, but idle is at 200 rpms and when i rev it up and let off it idles down to nothing and dies out. that leads me to believe that the alt is putting plenty of juice for everything and making up for crappy bat.
good idea, but i don't think that's it. it's not really really sluggish on start up. just enough to notice. if the alt was bad wouldn't all the electrical not work well while driving it? i'm gonna check the voltage on the bat and see what's up.
the alternator may still be working properly, just when you shut your jeep off it may drain your battery just enough. my mustang started up every time. sometimes hard sometime not. but it idled low and even lower with the a/c on. like landocomando said just bring it to one of the parts stores for a free test.
2013 Jeep Patriot 4x4 FD1 5spd
2004 R6 lowered, stretched, full exhaust, HIDs etc
2004 TJ Columbia package long armed w/ 33's (Sold)
2005 WK, v6 QT1 (girlfriends)
When the battery is low enough, the engine will barely idle and it can even stall. Have the battery load tested. The alternator depends on the battery to put out power so if the battery is dead or near dead, the alternator will be dead or near dead too.