Loss of power after overheat - JeepForum.com
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 > MJ Comanche Technical Forum > Loss of power after overheat

The Cure for your Tie Rod Roll!FS: Wrangler RGB Multicolor Fog Light LEDs: Awesome EffectIntroducing MONSTALINER™ UV Permanent DIY Roll On Bed Line

Unread 09-04-2013, 02:13 PM   #1
Registered User
1988 MJ Comanche 
Join Date: Sep 2013
Location: Sunnyvale, Ca
Posts: 1
Loss of power after overheat

I overheated to the point of engine stall after a bad coolant leak. After replacing lost fluid and field patching the leak engine ran OK and I've put a few thousand miles on it since. But I've noticed a significant loss of power (and it sounds like I have a mild misfire at full throttle as well), and 20% lower gas mileage. Noticed engine is running a little rich (blackish tailpipe as opposed to dark brown before), but plugs are clean. No indication of blow-by (oil clean, no visible smoke from tailpipe). No trouble codes. No fluid losses (beyond what deteriorating gaskets have been causing over the last ten years).

FYI 373,000 on original engine w/ no replacements other than typical maintenance (e.g. TPS, O2, crankshaft position sensors, plugs/wires/cap/rotor in the last two years).

Any idea what the problem might be?

1988 Jeep Comanche
4L, 4x4 5 speed manual

ATjeep42 is offline   Reply With Quote Quick reply to this message
Unread 09-05-2013, 02:46 PM   #2
Registered User
1988 MJ Comanche 
Join Date: Aug 2013
Location: Flagstaff, ARIZONA
Posts: 46
Not to stray from the topic but you can scan your '88 MJ? I have the same truck ('88, 4L, manual etc) and I've had the dash apart a couple times messing with the dash lights and new radio and not once have I seen anything that I could use to scan the truck.
TrucksBootsNGun is offline   Reply With Quote Quick reply to this message
Unread 09-08-2013, 06:37 PM   #3
Registered User
1992 XJ Cherokee 
Join Date: Oct 2007
Location: Rosamond, CA
Posts: 652
Start with the usual tuneup/sensors/fuel pressure items. Other than those... Hmmm.... I'm just thinking out loud here...

That's a lot of miles. Partially clogged fuel filter will show up as loss of power at heavy loads (high revs, or full throttle.) Or...
Camshaft is wearing out? (not as much lift at the valves.) Or...
The overheat softened the valve springs so now they float at high revs? (misfire)

Start with the easy stuff first...
The road goes on forever, the party never ends....
wgirvine is offline   Reply With Quote Quick reply to this message

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:


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.

Thread Tools

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.