quick idle question
#1
Member
Thread Starter
Join Date: Apr 2012
Location: illinois
Posts: 157
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
quick idle question
ok so my new 99 xj 4.0 has a rough idle that feels like a misfire almost every 3 or 4 seconds. so i replaced cap and rotor, plugs (champions) and plug wires and threw in some fuel additive in the tank. rough idle still continues every 3 or 4 seconds. while driving it feels fine its just at idle wether its in park or in gear. motor mounts look good too. should i look into fuel injectors or o2 sensors? what do you guys think?
#4
Member
Thread Starter
Join Date: Apr 2012
Location: illinois
Posts: 157
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
no check engine light on and the bulb does work. i also did the gauge check. th eone where you hold down the trip button and turn the key. did the parameters fine. no codes.
#6
CF Veteran
Join Date: Aug 2011
Location: Blue Springs, MO
Posts: 1,031
Likes: 0
Received 2 Likes
on
2 Posts
Year: 1993
Model: Grand Cherokee
Engine: 4.0L Laredo
I'd clean the IAC and check the TPS.. as above, i'd replace that old O2 sensor (pre cat) too. Other than the 'miss', does it idle ok? I mean not too high or low?
#7
CF Veteran
Join Date: Oct 2011
Location: Seal Beach, CA
Posts: 4,440
Likes: 0
Received 2 Likes
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
Clean the throttle body with TB cleaner, scrub the IAC with some carb cleaner and an old toothbrush, test the TPS to make sure it is functioning properly, and consider replacing the upstream o2 sensor.
What kind of oil filter are you running? I'd change the oil and oil filter (if you have not done so recently) Do some research on filters to find a good one.
Check your exhaust manifold for cracks. That could cause a rough idle too.
Use some Seafoam in the brake booster vacuum line going to the intake manifold (search YouTube for this, there's a lot of good videos showing you exactly where this line is and how to do it)
What kind of oil filter are you running? I'd change the oil and oil filter (if you have not done so recently) Do some research on filters to find a good one.
Check your exhaust manifold for cracks. That could cause a rough idle too.
Use some Seafoam in the brake booster vacuum line going to the intake manifold (search YouTube for this, there's a lot of good videos showing you exactly where this line is and how to do it)
Thread
Thread Starter
Forum
Replies
Last Post
jurazov
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
12
07-20-2023 04:13 AM
Jamesmon4
Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!
1
08-16-2016 09:04 PM
Tcq192
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
7
10-23-2015 09:25 AM
WomanNeedsJeepExpertise
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
21
09-10-2015 06:01 PM
australian_expat
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
4
09-02-2015 09:02 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)