1986 comanche. Rough idle, could it be the fuel injector? - 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 > 1986 comanche. Rough idle, could it be the fuel injector?

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineBrand New! Quadratec LED Headlights!New Vendor - ARTEC Industries Battery Mounts

Unread 01-22-2013, 12:52 PM   #1
Registered User
Join Date: Jul 2012
Posts: 7
Recently I've began to try and solve the issue of my comanche's rough idle. It has the 2.5l in it. Im getting about 15-16 mpg in. I know jeep isn't known for good fuel economy... But that low for a 4 banger?! I had a major vacuum leak at the bottom of the TBI where the block connects the 4 lines. I took the block out and fitted about 2 inches pieces of vacuum line for all 4 lines and voila, no more leak. I took it out to do some errands it still has somewhat of a rough idle. It definitely helped but when the truck is on and not moving the idle runs up and down in RPMs. Someone I work with told me the fuel injector could be clogged and said they should make a cone like spray onto the butterfly valve in the throttle body. When I checked mine it just sprays it in an unorganized burst onto the valve. Could I possibly need a new injector? I bought a refurb one 2 years ago to get the truck itself running because it didn't have one at all. But those 2.5 injectors are fairly expensive. I want to see what other simple things it could be before I fork over 125 bucks for one.

Last edited by colinkx250f; 01-22-2013 at 01:02 PM..
colinkx250f is offline   Reply With Quote
Unread 01-23-2013, 06:43 AM   #2
Web Wheeler
cruiser54's Avatar
1990 MJ Comanche 
Join Date: Oct 2009
Location: Prescott, Arizona
Posts: 10,051
Intake manifold bolts tight?

BG44K in the fuel tank to clean that injector.
Originally Posted by chris87xj View Post
If you own a Renix Jeep, you'll want to check this out. >

An index to over 25 write-ups can be found in Post #1.

Cruiser's Mostly Renix Tips
My Jeep Technical Photos

cruiser54 is offline   Reply With Quote
Unread 01-23-2013, 08:27 AM   #3
Registered User
Join Date: Jul 2012
Posts: 7
Intake manifold is tightened down. I had to put a gasket in for it about a month ago
colinkx250f is offline   Reply With Quote

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.