Spotty hesitation and idle - 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 Wrangler Forums > YJ Wrangler Technical Forum > Spotty hesitation and idle

Want to be able to SEE? DOT Approved Headlights for under Coil Spring Options from Ruffstuff!Flush Mount LED Bumper Lights, CREE

Reply
Unread 08-15-2006, 06:47 PM   #1
sentinal02
H2 Recovery Team Member
 
sentinal02's Avatar
1992 YJ Wrangler 
 
Join Date: Feb 2003
Location: New York
Posts: 6,688
Spotty hesitation and idle

Hey guys, looking for some opinions on this one.
The past two days the jeep has started hesitating in all gears when i try and accelerate. it doesn't happen every time though. ran fine to the store last night, come back out and it would hesitate. go for a little while and it would go away. this all happened out of the blue with no gradual loss of power or any other indication that anything was wrong. also it tends to idle erratically when it happens, ie drops to 400 rpms climbs to 800 drops again, and keeps on cycling like that. this morning i started it, it went to stall so i blipped the throttle and it backfired, sounded like it was on the exhaust side. since then it hasn't done the hard hesitation i was getting but i THINK it's still a little sluggish. could be that i'm just paranoid though. this is all before i've done any work to it. since this morning i've done a full tune up except for the O2 sensor. the rest (plugs, wires, cap, rotor, air and fuel filters) were changed. I don't notice any difference but like i said it wasn't acting up after that backfire this morning and i put close to 30 miles on it between that start and doing the tune up. the exhaust is new (maybe 3000 miles) from the manifold back. the O2 is about 30K miles old. from here i'm thinking one of these 4:

O2
Fuel pump
Coil
TPS

the plugs looked perfect when i pulled them so i'm kind of ruling out the coil. they were however gapped between .055 and .067 which is almost double the .035 spec. it was fairly even on all four plugs however and the burn pattern is a nice even coat of tan. seems to me that while they were due for a change they didn't seem to be the cause of the problem, or indicate that i'm fouling out or running lean. any thoughts guys?

__________________
RIP: '88 YJ 2.5L Ax-5 NP231
Posi-Loked. Herculined. Optima yellow top. 1" Shackle, 2" BDS. Cragar 397's Aussie front.

92 YJ 4.0L Ax-15 231
5" springs, 1" shackle 31's or 35's depending on my mood
sentinal02 is offline   Reply With Quote Quick reply to this message
Unread 08-16-2006, 10:43 AM   #2
King03Kev
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2005
Location: NJ
Posts: 615
Is it possible you just got a bad tank of gas, maybe a little water in the gas that after backfire cleaned out the injectors. Just guessing because it sounds like you checked just about everything else.
__________________
kevyj87 '87 I6 5spd, 215,000+ miles, Herced, Nuttered, Weber, HEI, RE 4", 1" BL, 4:11's, np231, 33x12.5's, SYE & shaft, 1" brown dog mm, home made bumpers front & rear, Ramsey 8,000lb winch
King03Kev is offline   Reply With Quote Quick reply to this message
Unread 08-16-2006, 03:51 PM   #3
sentinal02
H2 Recovery Team Member
 
sentinal02's Avatar
1992 YJ Wrangler 
 
Join Date: Feb 2003
Location: New York
Posts: 6,688
Quote:
Originally Posted by King03Kev
Is it possible you just got a bad tank of gas, maybe a little water in the gas that after backfire cleaned out the injectors. Just guessing because it sounds like you checked just about everything else.
yeah, was thinking that myself as well. mainly because this tank was from a station that i don't usually fill up at being i was on a long trip. i dumped in some STP fuel system cleaner with the new tank of gas yesterday so we'll see. right now the hesitation seems to be gone, but it's idling a bit higher than normal and when i first start it up in the morning it idle rough until the engine starts warming up. gonna check for vac leaks tomorrow.
__________________
RIP: '88 YJ 2.5L Ax-5 NP231
Posi-Loked. Herculined. Optima yellow top. 1" Shackle, 2" BDS. Cragar 397's Aussie front.

92 YJ 4.0L Ax-15 231
5" springs, 1" shackle 31's or 35's depending on my mood
sentinal02 is offline   Reply With Quote Quick reply to this message
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.
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:

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.


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.