1990 YJ 2.5 4 Cylinder: Bad idle, back fire, lean, rich, missing, wont stay cranked - 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 Wrangler Forums > YJ Wrangler Technical Forum > 1990 YJ 2.5 4 Cylinder: Bad idle, back fire, lean, rich, missing, wont stay cranked

The Original 3/8" Ruffstuff Diff Cover!Ruffstuff Axle Simple Swap Kit!The Ruffstuff NOT Universal 4 Link Kit!

Unread 07-14-2013, 05:07 PM   #1
Registered User
1990 YJ Wrangler 
Join Date: Jul 2013
Location: Orange, Texas
Posts: 1
1990 YJ 2.5 4 Cylinder: Bad idle, back fire, lean, rich, missing, wont stay cranked

Hey guys I am having a huge problem with my jeep. This is the first jeep I have owned so I am kinda in the dark about them. My problems I am having is after a year a driving without any problems all the sudden it died while going about 40 MPH then it cranked right up after that it start back firing really bad couldn't get up enough RPM's to get out of first gear had to be towed home. Since the problem started I have changed a few things that I have read on this forum but it seems like every time I change something a new problem pops up. The list of things I have changed is spark Plugs, O2 sensor, TPS, injector and crankshaft postition sensor. I took apart the fuel pressure regulator and checked it and it seemed fine no cracks or damage. Since I have done all this things seems to be getting worse. Now 2 of my plugs are very lean and the other 2 are pretty rich. Not sure how that happens. The only other sensor I know that control fuel/air mixture is the MAP sensor should that be a option? or at this point is it mechanical and not electrical?..please help me out here I am running out of options before I have to pay someone to fix it. Thanks in advance

Tex0ffroad is offline   Reply With Quote Quick reply to this message

backfires , lean , misfire yj , rich , wont run

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.

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.