Lumpy Idle but runs great-Any ideas?
07-21-2011, 12:03 AM
#1
Member
Thread Starter
Join Date: Jun 2011
Location: Southern California
Posts: 146
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1997
Model: Cherokee
Engine: 4.0 Liter
Lumpy Idle but runs great-Any ideas?
I have a lumpy idle on my 97 4.0. Feels like a miss. Off idle it runs great. I checked fuel pressure to be 43 psi at idle. Any ideas on a fix?
Thanks,
Flash
Thanks,
Flash
07-21-2011, 12:26 AM
#2
CF Veteran
Join Date: Jun 2011
Location: Southern Idaho
Posts: 1,023
Likes: 0
Received 1 Like
on
1 Post
Year: 1994
Model: Cherokee
Engine: 4.0 L/242 CID I-6 High Output MFI
Idle air control. You need to clean it and the throttle body. Takes fifteen minutes, two cans of throttle body cleaner, and a toothbrush.
07-21-2011, 03:14 AM
#3
Newbie
Join Date: Jul 2011
Location: Lincoln, Nebraska
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001
Model: Cherokee
Engine: 4.0
the aic and throttle body is definitely where i'd start. i used seafoam when cleaning mine (after removing the throttle body). 43 psi seems a little low to me but if it's just the idle then don't worry. throttle position sensor is another part that is notorious for going bad and causing idle problems in chryslers. how long have you had yer ride? how many miles? cheers!!
07-22-2011, 10:32 AM
#4
Member
Thread Starter
Join Date: Jun 2011
Location: Southern California
Posts: 146
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1997
Model: Cherokee
Engine: 4.0 Liter
I didnt know it had a TPS (Throttle position sensor). Where is it located?
Thanks for the responses...going to clean the IAC and TB today.
Flash
Thanks for the responses...going to clean the IAC and TB today.
Flash
07-22-2011, 01:19 PM
#6
Seasoned Member
Join Date: Jun 2011
Location: Catasauqua PA
Posts: 287
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
Originally Posted by djb383
Lumpy idle.......was this guy possibly the previous owner? LOL
Video Link: http://www.youtube.com/watch?v=pzG5b80KHvw&feature=related
Video Link: http://www.youtube.com/watch?v=pzG5b80KHvw&feature=related
Sent from my iPhone using CherokeeFM
07-22-2011, 01:20 PM
#7
Seasoned Member
Join Date: Jun 2011
Location: Catasauqua PA
Posts: 287
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
Originally Posted by CattyXJ
The TPS is the sensor on the throttle body closest to the motor, it's round. And x2 on using seafoam. Run it through the TB while the motor is running. That alone may fix the issue.
Sent from my iPhone using CherokeeFM
Sent from my iPhone using CherokeeFM
Trending Topics
07-22-2011, 01:26 PM
#8
Seasoned Member
Join Date: Jan 2010
Location: JERSEY ALL DAY
Posts: 251
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1989
Model: Cherokee
Engine: 4.0L
Lumpy idle.......was this guy possibly the previous owner? LOL
‪worked 202 idle‬‏ - YouTube
‪worked 202 idle‬‏ - YouTube
haha I was thinking the same thing
07-22-2011, 01:45 PM
#9
Junior Member
Join Date: Jul 2011
Location: Boston
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2000
Model: Cherokee
Engine: 4.0
Most likely a bad wire. I had the same thing going on in my last cherokee and replacing the bad wire fixed the lumpy idling problem.
07-22-2011, 09:59 PM
#11
CF Veteran
Join Date: Feb 2010
Location: Oroville, CA
Posts: 12,367
Likes: 0
Received 19 Likes
on
18 Posts
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
Look for vacuum leaks, check the plastic line that goes to the MAP sensor if it is firewall mounted, do a compression test and see if any of the cylinders are low on compression. Low compression could mean a burnt valve or worn rings.
07-22-2011, 10:18 PM
#12
Seasoned Member
Join Date: Jun 2011
Location: Catasauqua PA
Posts: 287
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
Before you start getting crazy on valves and vacuums and looking for broken wires...have you given it a tune up lately? Like plugs cap wires filters, etc.? There's literally like 50 things that can cause a rough idle. Start with the simple stuff that you should be doing yearly anyway, then start looking for the odd things.
Sent from my iPhone using CherokeeFM
Sent from my iPhone using CherokeeFM
07-23-2011, 09:42 PM
#13
Newbie
Join Date: Jul 2011
Location: Lincoln, Nebraska
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001
Model: Cherokee
Engine: 4.0
Agreed with Cattyxj, start cheap and work deeper into yer pocketbook from there. The first ? is how mechanically adept are you? Are you able to do the work yourself? Again start cheap...
07-24-2011, 12:23 AM
#15
CF Veteran
Join Date: Feb 2010
Location: Oroville, CA
Posts: 12,367
Likes: 0
Received 19 Likes
on
18 Posts
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
Before you start getting crazy on valves and vacuums and looking for broken wires...have you given it a tune up lately? Like plugs cap wires filters, etc.? There's literally like 50 things that can cause a rough idle. Start with the simple stuff that you should be doing yearly anyway, then start looking for the odd things.
Sent from my iPhone using CherokeeFM
Sent from my iPhone using CherokeeFM