Author Topic: Rough idle  (Read 1983 times)

Offline CnoteTJ

  • Honorary Member
  • Rock Crawler
  • ***
  • Posts: 475
    • Facebook
Rough idle
« on: April 22, 2008, 02:05:15 PM »
So, yesterday i noticed my jeep was idling rough on the way into work.  Once I got to spend a little time on it I noticed that the vacuum line for my heater and cruise control(havent used either in a long time) had come undone.  Now, when I push in the clutch and pop her outta gear she starts loping like a drag racer with a heavy cam  >:( (between 500 rpm and 1000rpm)  any ideas on what the problem might be?  Let me know...
2011 Black Jeep Wrangler Rubicon
4" FT Long Arm w/ CRC link and 35" MTR/K's
Some armor and performance goodies!

www.northridge4x4.com    www.offroadevolution.com   www.full-traction.com

Offline rocket

  • Trail Master
  • *****
  • Posts: 2802
  • That is what i call, "Flexing"
    • my webshots photo site - lots of wheeling pics!
Re: Rough idle
« Reply #1 on: April 22, 2008, 02:24:58 PM »
sounds like a vacuum leak.  check all lines, check manifold vacuum, check pcv valve.
1973 Chevy El Camino: 383 sb, lots of power
2004 Toyota Tacoma TRD 3.4L xtra cab 2.5" skyjacker coilovers/leafs, 32x11.5-15" Super Swamper TSL/SXs, Bent-up front bumper, smittybilt winch, 4xInovations sliders, Bud-built skids, custom rear bumper/light bar, hella lights, "custom" body work

Offline HOT-ROD

  • Trail Master
  • *****
  • Posts: 2190
Re: Rough idle
« Reply #2 on: April 22, 2008, 05:05:14 PM »
check your idle adjustment. sometimes it backs off and lowers your idle. i would lean towards a vacuum leak with the clutch master. seem likely when you drop off the pressure the engine drops rpm's.

Offline CnoteTJ

  • Honorary Member
  • Rock Crawler
  • ***
  • Posts: 475
    • Facebook
Re: Rough idle
« Reply #3 on: April 23, 2008, 08:38:18 PM »
more info on this...this only occurs when I am driving somewhere, after sitting for two minutes it is fine
2011 Black Jeep Wrangler Rubicon
4" FT Long Arm w/ CRC link and 35" MTR/K's
Some armor and performance goodies!

www.northridge4x4.com    www.offroadevolution.com   www.full-traction.com

Offline Seabee_BUC

  • Honorary Member
  • Trail Master
  • ***
  • Posts: 1106
  • Yeah she's fast...Terrible in the rocks I'm sure!
Re: Rough idle
« Reply #4 on: April 23, 2008, 09:47:44 PM »
I would suggest it's the fuel filter. Under load and driving, it could get starved for fuel especially with all your performance mods. When it sits, the engine gets plenty, because the pump can keep up with it. With a clogged filter, flow is severly diminished. I'd look into an adjustable fuel pressure regulator too, just bumping up 2-3 lbs. is a fine improvement in fuel delivery. It might not be $$ friendly due to gas prices right now however.

Offline CnoteTJ

  • Honorary Member
  • Rock Crawler
  • ***
  • Posts: 475
    • Facebook
Re: Rough idle
« Reply #5 on: April 23, 2008, 11:49:53 PM »
after re verifying every vacuum line, and looking for any other visible problems today, i talked to one of my mechanic buddies (ASE certified), after explaining my problems he recommended taking the neg cable off the battery for 5 minutes since i had that vacuum line disconnected, to reset the computer.  i did so and after a short drive around new london, only once did I have a slight problem at idle(it just hung low round 500 rpm) but no more loping, im working 3rd shift the rest of the week starting tonight so ill see how she acts after a highway mile.  hopefully no more problems *fingers crossed*  like fuel filters, iac valves, and pcv valves.  thanks for the ideas and help guys!!
2011 Black Jeep Wrangler Rubicon
4" FT Long Arm w/ CRC link and 35" MTR/K's
Some armor and performance goodies!

www.northridge4x4.com    www.offroadevolution.com   www.full-traction.com