Rough idle, Low Power, Idle Vacuum Steady 15 inHg - Page 2 - 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 Cherokee & Comanche Forums > XJ Cherokee Technical Forum > Rough idle, Low Power, Idle Vacuum Steady 15 inHg

Clayton Off Road WJ Long Arm Kits!Baseline 4x4 Lifetime Warranty 4340 Chromoly Axle Shaft KiClayton Off Road - JK Prototype Gas Tank Skid

Reply
Unread 11-14-2011, 08:16 PM   #16
cruiser54
Web Wheeler
 
cruiser54's Avatar
1990 MJ Comanche 
 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 10,036
2 seconds isn't too slow.

cruiser54 is offline   Reply With Quote
Unread 11-14-2011, 11:35 PM   #17
Double0Jeep
Registered User
2000 XJ Cherokee 
 
Join Date: Nov 2011
Location: Mountain View, CA
Posts: 11
Ok, things are getting interesting now. The Jeep is now running so bad that it is no longer drivable. Good news is I finally got a CEL!

P0400 Exhaust Gas Recirculation Flow Malfunction

That bad news is that the 4.0L does not have an EGR Valve!! What going on here? Has anyone ever seen or heard of this before?

TIA!
Double0Jeep is offline   Reply With Quote
Unread 11-15-2011, 01:02 AM   #18
Double0Jeep
Registered User
2000 XJ Cherokee 
 
Join Date: Nov 2011
Location: Mountain View, CA
Posts: 11
Quote:
Originally Posted by Double0Jeep View Post
Ok, things are getting interesting now. The Jeep is now running so bad that it is no longer drivable. Good news is I finally got a CEL!

P0400 Exhaust Gas Recirculation Flow Malfunction

That bad news is that the 4.0L does not have an EGR Valve!! What going on here? Has anyone ever seen or heard of this before?

TIA!
It looks like this is just a symptom of the low engine vacuum.

P0400-P0405
The PCM tests the exhaust gas recirculation (EGR) system during deceleration by momentarily commanding the EGR valve to open while monitoring the manifold absolute pressure (MAP) sensor signal. When the EGR valve is opened, the PCM should see a proportional increase in MAP.

If the expected increase in MAP is not seen, the PCM notes the amount of error that was detected and adjusts an internal fail counter towards a fail threshold level. When the fail counter exceeds the fail threshold level, the PCM will set this DTC. The number of test samples required to accomplish this may vary according to the amount of detected flow error.
Double0Jeep is offline   Reply With Quote
Reply

Tags
4.0l , low power , rough idle , surging , vacuum
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.