Rough Idle/Sputter/ intake back fire No CEL

Wick3dMrB

New Member
Original poster
Joined
Jul 11, 2024
Messages
15
Location
Houston
Been browsing this forum for a good while now and haven’t seen any solutions for my problem. I have a 2000 TJ 4.0 with 90k miles. Over the last few months I’ve had an issue where first startup of the day or if it has been sitting for a few hours it will start up fine but shortly after will start to sputter and miss. If apply any throttle it will bog and try and die and backfire in the airbox. After a few minutes it will jump up to 3k rpm and will idle perfectly fine.
No codes

new plugs, coil pack, and B2S1 o2. Cal emissions. Throttle has been cleaned. Any idea what the issue could be?

PS MPG is between 10-13 hwy not sure if it is related rolling 33s
 
Been browsing this forum for a good while now and haven’t seen any solutions for my problem. I have a 2000 TJ 4.0 with 90k miles. Over the last few months I’ve had an issue where first startup of the day or if it has been sitting for a few hours it will start up fine but shortly after will start to sputter and miss. If apply any throttle it will bog and try and die and backfire in the airbox. After a few minutes it will jump up to 3k rpm and will idle perfectly fine.
No codes

new plugs, coil pack, and B2S1 o2. Cal emissions. Throttle has been cleaned. Any idea what the issue could be?

PS MPG is between 10-13 hwy not sure if it is related rolling 33s

stab in the dark but have you checked if the cats are clogged and your IAC is clean?
 
stab in the dark but have you checked if the cats are clogged and your IAC is clean?

I haven't checked if cats are clogged and not sure how to. And I assumed the IAC got cleaned when I cleaned the throttle body (sprayed TB cleaner in it and wiped it out) the throttle.body looks as if its heavily oxidized not sure if that would effect anything.
 
I haven't checked if cats are clogged and not sure how to. And I assumed the IAC got cleaned when I cleaned the throttle body (sprayed TB cleaner in it and wiped it out) the throttle.body looks as if its heavily oxidized not sure if that would effect anything.

There's a few videos on YouTube on how you can check your cats. Mine clogged and I couldn't get past 10 mph...you'd be surprised how bad it can make your engine run

https://wranglertjforum.com/threads/how-to-clean-your-iac-idle-air-controller-valve.662/

This is a little more in depth on cleaning the valve