Bouncing idle??? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > WK Grand Cherokee & XK Commander Forum > Bouncing idle???

Bill Baird Motorsports DIY parts - NalinMFG.comFS: 2007-2013 Jeep Wrangler "HALO" Angel Eye KitFS: Wranger BRIGHT License Plate LED! Just $3! Great value

Reply
Unread 09-05-2012, 09:26 PM   #1
08Titan
Registered User
2007 JK Wrangler 
 
Join Date: Aug 2010
Location: Orangeville, PA, Pennsylvania
Posts: 360
Bouncing idle???

My wifes 05 limited 4.7 has been having a bouncing idle lately. It'll go from 500-1,000+ rpms back and forth over and over and almost stall when it comes back down. It does it the worst after driving it 5-10 miles or more but it also does it sometimes right on initial fire up. The plugs look good and have about 20k miles since I changed them last(stock champions). I looked around and saw that most of the troubles come from a dirty TB or bad IAC(idle air control) motor so I cleaned the TB and replaced the IAC motor and it seemed to have gotten slightly better after that for a few days. Now tonight it's right back to the same thing. Any ideas on what this might be?? Maybe bad EGR? It's the stock EGR and the jeep has ~84,000 on it. Any info would be greatly appreciated.

It runs smooth and strong and gets the same crappy 15mpg it always gets. The only thing it's doing wrong is the idle. There's also no codes coming up or a check engine light.

__________________
2007 JK unlimited rubicon, red rock crystal pearlcoat, rc 2.5" spacer lift, 35x12.50 goodyear mtr/k mounted on black 15x8" mb72's. (Mine)

2005 WK Limited 4.7, QTII, Midnight blue pearlcoat. (Hers)
08Titan is offline   Reply With Quote
Unread 09-06-2012, 01:04 AM   #2
2SH3A
Registered User
 
Join Date: Jul 2012
Posts: 65
I'm in the same exact situation miles and all. I heard its the EGR. Very common issue with the 4.7. I'm not getting any codes either. Have you checked tranny fluid? My WK runs really good except the rough idle after highway driving. It's a weird deal and I hope we can figure it out. Have you tried to service the fuel system? Seafoam?
2SH3A is offline   Reply With Quote
Unread 09-06-2012, 08:08 AM   #3
shudog
Registered User
2012 WK 
 
Join Date: Nov 2004
Posts: 324
Throttle Position Sensor, located on the throttle body, $35 part, 10 min install. Had the same issues with mine, fixed the idle, smoothed out the shifting.
__________________
Previously owned jeeps:
'06 Grand Cherokee Limited w/4.7L V8 & QD2
'98 Grand Cherokee Limited w/5.2L V8 & Quadra Trac - sold at 230k miles
shudog is offline   Reply With Quote
Unread 09-06-2012, 03:54 PM   #4
08Titan
Registered User
2007 JK Wrangler 
 
Join Date: Aug 2010
Location: Orangeville, PA, Pennsylvania
Posts: 360
Thanks guys. I'm gonna start with the tps because it's cheaper and easier to replace. Then I'll do the egr if that doesn't work.
__________________
2007 JK unlimited rubicon, red rock crystal pearlcoat, rc 2.5" spacer lift, 35x12.50 goodyear mtr/k mounted on black 15x8" mb72's. (Mine)

2005 WK Limited 4.7, QTII, Midnight blue pearlcoat. (Hers)
08Titan is offline   Reply With Quote
Unread 09-11-2012, 05:59 PM   #5
b1llyw
Registered User
2007 XK Commander 
 
Join Date: Jul 2004
Location: Connecticut
Posts: 129
I'm having the same issue on my XK, bouncy idle, funny shifting. Going to clean throttle body and sensors first. I'm probably not lucky enough for that to fix it. I'm sure I'll end up replacing the TPS.
__________________
Bill White - http://www.revelation320.org

07 Commander Sport 4x4, 4.7, Sirius Stratus, Factory RAK 6-CD Changer, MP3, Cassette, Superchips
b1llyw is offline   Reply With Quote
Unread 09-11-2012, 06:09 PM   #6
08Titan
Registered User
2007 JK Wrangler 
 
Join Date: Aug 2010
Location: Orangeville, PA, Pennsylvania
Posts: 360
Update: The TPS fixed it. Running like a champ now. Only $30 at napa.
__________________
2007 JK unlimited rubicon, red rock crystal pearlcoat, rc 2.5" spacer lift, 35x12.50 goodyear mtr/k mounted on black 15x8" mb72's. (Mine)

2005 WK Limited 4.7, QTII, Midnight blue pearlcoat. (Hers)
08Titan is offline   Reply With Quote
Unread 09-12-2012, 02:16 PM   #7
b1llyw
Registered User
2007 XK Commander 
 
Join Date: Jul 2004
Location: Connecticut
Posts: 129
Changed the TPS. Drove it around town, seemed fine. Need to get it up on highway to be sure. Major PITA getting the Torx screws out. I must have come close to busting the head off one of them. Seriously corroded when it came out.
__________________
Bill White - http://www.revelation320.org

07 Commander Sport 4x4, 4.7, Sirius Stratus, Factory RAK 6-CD Changer, MP3, Cassette, Superchips
b1llyw is offline   Reply With Quote
Unread 09-12-2012, 03:15 PM   #8
b1llyw
Registered User
2007 XK Commander 
 
Join Date: Jul 2004
Location: Connecticut
Posts: 129
Official Mopar TPS Torx Screw Removal Tool

Redneck engineering..
2012-09-12-12.28.59.jpg  
__________________
Bill White - http://www.revelation320.org

07 Commander Sport 4x4, 4.7, Sirius Stratus, Factory RAK 6-CD Changer, MP3, Cassette, Superchips
b1llyw is offline   Reply With Quote
Unread 09-13-2012, 01:43 AM   #9
geoffh
Registered User
2005 WK 
 
Join Date: Oct 2010
Location: Rapid City, South Dakota
Posts: 149
I am having a similar issue with my 5.7 hemi. It has the bouncing throttle at idle and at times will shut down associated with an oil light after shutting down. All my servicing is good and I have already changed the EGR valve since I heard that was the most common thing to go wrong with the HEMIs. Still have the issue after the EGR though. Any of you HEMI guys out there have this same issue? It only happens everyone now and then after initial cold start and if I rev up the engine it goes away after that.
__________________
'05 WK Limited, QD-II, 5.7L HEMI, K&N CAI, Gobi Rack, Fast Man TB, 4" Super Lift, 4" JBA coilovers, 285/70-17 Mickey Thompson Baja, 17" AEV Pintler, Diablo Sport Predator, Steel Armadillo console safe, JBA UCA, Bilstein 7100 shocks, 4xGuard rock sliders/belly& front skid, ARB bull bar, Saguaro rear bumper/tire carrier
geoffh is offline   Reply With Quote
Unread 09-13-2012, 06:06 AM   #10
shudog
Registered User
2012 WK 
 
Join Date: Nov 2004
Posts: 324
Do the Throttle Position Sensor. Should be a quick cheap fix. See if that cures the problem
__________________
Previously owned jeeps:
'06 Grand Cherokee Limited w/4.7L V8 & QD2
'98 Grand Cherokee Limited w/5.2L V8 & Quadra Trac - sold at 230k miles
shudog is offline   Reply With Quote
Unread 09-13-2012, 06:48 AM   #11
eprovenzano
Registered User
2005 WK 
 
Join Date: Jan 2006
Location: Wellsburg WV
Posts: 362
I 1st changed my spark plugs, (85K on OEM plugs), the engine ran a lot smoother, but the idle was still erratic. So I then changed the TPS, and it runs like a new Jeep.

Thanks for the suggestion guys.
__________________
2012 Grand Cherokee Limited Wk2 (Momma's)
2005 Grand Cherokee Limited, WK, 4.7 V8 currently rolling on Cooper Discovery 265 70 17's, with 1.25" spacers.,installed an OME HD lift sourced through Kolak.
1996 XJ 6 inch lift on 33's (Son's)
eprovenzano is offline   Reply With Quote
Unread 09-14-2012, 01:46 AM   #12
geoffh
Registered User
2005 WK 
 
Join Date: Oct 2010
Location: Rapid City, South Dakota
Posts: 149
I have an after market Fastman throttle body. I have no idea where the throttle position sensor is on the 5.7 hemi. I think its on the throttle body for the 4.7 but dont have a clue for the 5.7 that my jeep has. Any one have any ideas?
__________________
'05 WK Limited, QD-II, 5.7L HEMI, K&N CAI, Gobi Rack, Fast Man TB, 4" Super Lift, 4" JBA coilovers, 285/70-17 Mickey Thompson Baja, 17" AEV Pintler, Diablo Sport Predator, Steel Armadillo console safe, JBA UCA, Bilstein 7100 shocks, 4xGuard rock sliders/belly& front skid, ARB bull bar, Saguaro rear bumper/tire carrier
geoffh is offline   Reply With Quote
Unread 07-22-2014, 02:18 PM   #13
2SH3A
Registered User
 
Join Date: Jul 2012
Posts: 65
TPS did not fix mine. I heard if you slightly over fill the tranny fluid that will cure it. In extreme cases a reflash of the PCM is required. I'm in the middle of replacing my exhaust manifold so hopefully when I'm done the rough idle will go away. 05 4.7
2SH3A is offline   Reply With Quote
Unread 07-22-2014, 07:39 PM   #14
90grandoneer
Registered User
2006 WK 
 
Join Date: Apr 2008
Location: City of Trees
Posts: 1,681
I had this same issue with both my Hemi vehicles when I installed larger BBK throttle bodies....90mm on the WK and 85mm on the LX. The problem is in the PCM adaptive memory programming. I used my Autel MaxiDas DS708 to reset the engine adaptive memories, and that fixed it on both of them. A complete reset of all adaptives will take up to 50 run cycles to "memorize" your driving style. It took about 3-4 days (maybe 24 engine run cycles) before mine would behave like it should. Fuel economy also deteriorated during this period. If you've messed with the throttle body at all (like cleaning it), that could also cause it. Just disconnecting the battery may also cause it to require a relearn. Here's what the BBK folks say to do:
They call it, "Throttle Position/Gas Pedal relearn procedure for Chrysler/Dodge 5.7, 6.1, and 6.4 Hemi Engines. The Jeep 5.7 engines (and throttle bodies) are the same as the Chrysler/Dodge 5.7 engines.

1. Disconnect the battery for 5 minutes. (I would disconnect the Positive Cable and ground it. This will drain all the capacitors in the PCM.) Reconnect (or use a code reader to clear any stored codes in the computer.)
2. Turn ignition key to the "ON" position.....do not start the engine.
3. Slowly depress the gas pedal to the floor, then slowly release it. Do this three (3) times. Turn key off.
4. Now start the engine. The gas pedal is now in sync with the (larger) throttle body.

Even if you haven't installed a larger TB, give it a try and let us know if it works.
__________________
06 GCO, Dk Khaki, QDII, Flshing Hi 3rd Bk Lt, MDS "ON" Lt, Airtab Vortex Gens, Debadged, Fumoto Drain Valve, BT Catch Can, Chopped EGR Tube, SRT8 CAI, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tune App, DS Tuner, Cust tubular hdrs w/3 in Magnaflow/Xlerator AP Exh Sys, Bilsteins, SRT Springs/Sways, Cust Eng Cvr, SRT8 frt/rear bumpers, FRI Sidewinder Cam/6.1 valvetrain, SLP 25% UD Pulley, BBK true 90mm T-Body, SOS Ign Coils w/.060 spark plug gaps, SRT Reps with 265/45&295/40X20's.
90grandoneer is offline   Reply With Quote
Unread 07-23-2014, 05:16 PM   #15
2SH3A
Registered User
 
Join Date: Jul 2012
Posts: 65
I did the peddle thing with my Fastmans TB and just did a Seafoam treatment. No rough idle as of right now!

So far I've replaced:

TPS
EGR Valve
IAC
Spark Plugs
2SH3A is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.