Strange loss of Power...need help diagnosing - JeepForum.com

Reply
 
LinkBack Thread Tools
post #1 of 20 Old 10-30-2009, 08:02 AM Thread Starter
atomicflatulenc
Registered User
1985 CJ7 
 
Join Date: May 2007
Location: Pemberton, NJ
Posts: 520
Strange loss of Power...need help diagnosing

I've been having an issue lately with my 96 4.0L ZJ.

When I go over small bumps in the road, I sometimes lose engine power.

I need to find a direction to start from. Sensors maybe?

The only other time it will do the wierd thing is after I drive the 30 minutes at about 45...park and pick up my son...when I first accelerate it starts to go for a second and then nothing...I have to let up on the gas and then push the peddle back down to start accelerating again.

I've tried just keeping the peddle pressed and the ZJ just hesitates and won't go until I let up on the gas and try agian.

Weird...

Tell me someone has had this issue! Help!


'85 CJ7, 258 4.2 Howell TBI, NP435, twin sticked Dana300, 4.56 Yukon chromoly: Rear20-extra thick tubes, shaved,trussed,discbrakes,ARB: Front30- flipped tierod,Detroit EZ locker, warn hubs: 3.5" BDS YJ springs and booster, 35" Trxus M/T's, rhino'd, full roll cage, borgenson steering shaft, big daddy steering box bracket...Unknown OIL Leak(working on it...)
FOR SALE $6000
atomicflatulenc is offline  
Sponsored Links
Advertisement
 
post #2 of 20 Old 10-30-2009, 08:20 AM
4Slow9erHybrid
Registered User
1997 ZJ 
 
Join Date: May 2008
Location: Hopkinton
Posts: 748
Quote:
Originally Posted by atomicflatulenc View Post
I've been having an issue lately with my 96 4.0L ZJ.

When I go over small bumps in the road, I sometimes lose engine power.

I need to find a direction to start from. Sensors maybe?

The only other time it will do the wierd thing is after I drive the 30 minutes at about 45...park and pick up my son...when I first accelerate it starts to go for a second and then nothing...I have to let up on the gas and then push the peddle back down to start accelerating again.

I've tried just keeping the peddle pressed and the ZJ just hesitates and won't go until I let up on the gas and try agian.

Weird...

Tell me someone has had this issue! Help!
Try disconnecting the upstream O2 sensor (the one before the catalytic converter). Drive around for a few days and see if these symptoms disappear. If they do, you need a new GENUINE MOPAR sensor!!! Don't experiment with Bosch and other brands. The 4.0 is very picky about the O2 sensor. Remember, disconnecting the sensor is a test, not a cure! Don't plan on any 1000mi road trips with disconnected sensor.

1997 JGC Laredo 4.0 4x4 99900mi * 0W30 German Castrol since 75k * 225/75/R15 Firestone Destination AT on Ravine rims * winter 235/75/R15 Bridgestone Blizzak DM-V1 * UC suspension * Monroe Reflex Monotube shocks * factory skids * KOR steering brace * rear Addco SB * Magnaflow cat and cat back system * complete 5.9 interior
4Slow9erHybrid is offline  
post #3 of 20 Old 10-30-2009, 08:34 AM Thread Starter
atomicflatulenc
Registered User
1985 CJ7 
 
Join Date: May 2007
Location: Pemberton, NJ
Posts: 520
Do I need to get the MOPAR sensor from a dealer?

I did change the sensor back in june with a NAPA O2 sensor.

'85 CJ7, 258 4.2 Howell TBI, NP435, twin sticked Dana300, 4.56 Yukon chromoly: Rear20-extra thick tubes, shaved,trussed,discbrakes,ARB: Front30- flipped tierod,Detroit EZ locker, warn hubs: 3.5" BDS YJ springs and booster, 35" Trxus M/T's, rhino'd, full roll cage, borgenson steering shaft, big daddy steering box bracket...Unknown OIL Leak(working on it...)
FOR SALE $6000
atomicflatulenc is offline  
post #4 of 20 Old 10-30-2009, 08:32 PM
Jeep2k55
Registered User
2000 WJ 
 
Join Date: Nov 2008
Location: Kent
Posts: 58
I have noticed that if you have a leak in your transfer case and you lose fluid, you will also lose alot of power. Happened to me. Found out by accident. Had major power loss...felt gutless. And was doing random maintenance on it and decided to service the TC. Realized it was extremely low on fluid. Filled her back up and took her for a drive and the power was back. Maybe it was unrelated? I don't know for sure but that's my expirience
Jeep2k55 is offline  
post #5 of 20 Old 10-30-2009, 09:03 PM
JesseOR
Registered User
1993 ZJ 
 
Join Date: Oct 2009
Location: Eugene
Posts: 1,621
Reading the title, I would say Cat, but the symptoms you described, almost rule it out....

-Jesse-
GO DUCKS!

www.facebook.com/jesse.whitehargrove
JesseOR is offline  
post #6 of 20 Old 10-31-2009, 10:13 AM Thread Starter
atomicflatulenc
Registered User
1985 CJ7 
 
Join Date: May 2007
Location: Pemberton, NJ
Posts: 520
What cat... The only cat might be dead under the hood.

'85 CJ7, 258 4.2 Howell TBI, NP435, twin sticked Dana300, 4.56 Yukon chromoly: Rear20-extra thick tubes, shaved,trussed,discbrakes,ARB: Front30- flipped tierod,Detroit EZ locker, warn hubs: 3.5" BDS YJ springs and booster, 35" Trxus M/T's, rhino'd, full roll cage, borgenson steering shaft, big daddy steering box bracket...Unknown OIL Leak(working on it...)
FOR SALE $6000
atomicflatulenc is offline  
post #7 of 20 Old 10-31-2009, 10:27 AM
JesseOR
Registered User
1993 ZJ 
 
Join Date: Oct 2009
Location: Eugene
Posts: 1,621
Quote:
Originally Posted by atomicflatulenc View Post
What cat... The only cat might be dead under the hood.
Sooo, am I to gather from this that you cut out the CATYLITIC converter?

Because a clogged CAT will result in massive power loss.

-Jesse-
GO DUCKS!

www.facebook.com/jesse.whitehargrove
JesseOR is offline  
post #8 of 20 Old 10-31-2009, 10:44 AM
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Posts: 8,833
Quote:
Originally Posted by atomicflatulenc View Post
When I go over small bumps in the road, I sometimes lose engine power.
Try gently wiggling PCM connectors while engine running cold and see if you get hestitation.

Also try gently tapping the fuel pump, ASD, and tranny relays in the fuse box under the hood.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ZeeJay1997 is online now  
post #9 of 20 Old 10-31-2009, 10:59 AM Thread Starter
atomicflatulenc
Registered User
1985 CJ7 
 
Join Date: May 2007
Location: Pemberton, NJ
Posts: 520
Cat was all broken up inside and clogged. Its not anymore...

I need a babysitter, or I'll never get this solved!

'85 CJ7, 258 4.2 Howell TBI, NP435, twin sticked Dana300, 4.56 Yukon chromoly: Rear20-extra thick tubes, shaved,trussed,discbrakes,ARB: Front30- flipped tierod,Detroit EZ locker, warn hubs: 3.5" BDS YJ springs and booster, 35" Trxus M/T's, rhino'd, full roll cage, borgenson steering shaft, big daddy steering box bracket...Unknown OIL Leak(working on it...)
FOR SALE $6000
atomicflatulenc is offline  
post #10 of 20 Old 05-18-2010, 09:38 AM Thread Starter
atomicflatulenc
Registered User
1985 CJ7 
 
Join Date: May 2007
Location: Pemberton, NJ
Posts: 520
still having trouble with this and its getting worse...

'85 CJ7, 258 4.2 Howell TBI, NP435, twin sticked Dana300, 4.56 Yukon chromoly: Rear20-extra thick tubes, shaved,trussed,discbrakes,ARB: Front30- flipped tierod,Detroit EZ locker, warn hubs: 3.5" BDS YJ springs and booster, 35" Trxus M/T's, rhino'd, full roll cage, borgenson steering shaft, big daddy steering box bracket...Unknown OIL Leak(working on it...)
FOR SALE $6000
atomicflatulenc is offline  
post #11 of 20 Old 05-18-2010, 01:16 PM
murphydajeep
Registered User
1995 ZJ 
 
Join Date: Sep 2009
Location: Modesto, CA
Posts: 175
Quote:
Originally Posted by ZeeJay1997 View Post
Try gently wiggling PCM connectors while engine running cold and see if you get hestitation.

Also try gently tapping the fuel pump, ASD, and tranny relays in the fuse box under the hood.
I would think loose connection too, if it happens when your hittin a bump it could be jostling your connector around just enough to mess it up for a second. If it was a clogged cat wouldnt it be a consistent loss of power, almost sounds like your having a fuel delivery issue....bad map sensor, dirty intake?

When all else fails bust out the hammer and start hitting things that look like they are givin you the eye, swearing helps too, Percussive maintenance ftw.
murphydajeep is offline  
post #12 of 20 Old 05-18-2010, 08:19 PM
classicmetalman
Registered User
 
Join Date: May 2005
Location: SoCal
Posts: 457
Quote:
Originally Posted by murphydajeep View Post

When all else fails bust out the hammer and start hitting things that look like they are givin you the eye, swearing helps too, Percussive maintenance ftw.
Too funny I'd lean towards a loose connector somewhere

Robert
93 Laredo 4.0
96 Limited 4.0

Quote:
Originally Posted by murphydajeep View Post
I say you should still hit something just to let it know you mean business, or shake a hammer at it in a menacing fashion
classicmetalman is offline  
post #13 of 20 Old 05-18-2010, 09:27 PM
rooster51
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Location: Virginia Beach
Posts: 1,628
Im thinking, in no specific order, PCM or coil or CPS or any combination of the 3.
Happy hunting!

Terry

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
rooster51 is offline  
post #14 of 20 Old 05-19-2010, 08:12 AM Thread Starter
atomicflatulenc
Registered User
1985 CJ7 
 
Join Date: May 2007
Location: Pemberton, NJ
Posts: 520
Replaced the cap, rotor, plugs and wires last night. No issues on the test drive, and no issues for the 40 minute round trip to the babysitter's.

Not gonna say its fixed yet. Maybe if I go a week without a powerloss I'll say its fixed.

'85 CJ7, 258 4.2 Howell TBI, NP435, twin sticked Dana300, 4.56 Yukon chromoly: Rear20-extra thick tubes, shaved,trussed,discbrakes,ARB: Front30- flipped tierod,Detroit EZ locker, warn hubs: 3.5" BDS YJ springs and booster, 35" Trxus M/T's, rhino'd, full roll cage, borgenson steering shaft, big daddy steering box bracket...Unknown OIL Leak(working on it...)
FOR SALE $6000
atomicflatulenc is offline  
post #15 of 20 Old 05-19-2010, 10:23 AM
murphydajeep
Registered User
1995 ZJ 
 
Join Date: Sep 2009
Location: Modesto, CA
Posts: 175
Quote:
Originally Posted by atomicflatulenc View Post
Replaced the cap, rotor, plugs and wires last night. No issues on the test drive, and no issues for the 40 minute round trip to the babysitter's.

Not gonna say its fixed yet. Maybe if I go a week without a powerloss I'll say its fixed.
I say you should still hit something just to let it know you mean business, or shake a hammer at it in a menacing fashion
murphydajeep is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Strange front end noise... I'm at a loss crazymjb ZJ Grand Cherokee Forum 3 05-26-2009 05:24 PM
ZJ power steering intermittant power loss Coblue ZJ Grand Cherokee Forum 2 12-06-2008 12:49 PM
Power Loss josezj95 ZJ Grand Cherokee Forum 22 10-27-2008 03:54 PM
loss of power dirtneverhurt ZJ Grand Cherokee Forum 0 07-25-2008 06:17 PM
5.2L Loss of Power li'l jeep ZJ Grand Cherokee Forum 24 02-15-2007 08:14 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome