Bank 1 lean code after cleaning throttle body and IAC

[Airparis33]

Sorry for the double posting, I realized I added this in the wrong forum too late.

Thank God for Jeep forums, I'm at a loss.
I'm in no way a mechanic, but can handle minor jobs.. my 99 4.0 was idling rough intermittently, and I cleaned the throttle body/ IAC sensor/ and replaced the TPS sensor. After that I got the Bank 1 Lean code for the first time.
Mine is older (had for a couple years now), and I dont know what has or hasn't been done- so I figured some sensor changes couldn't hurt, even if not the exact issue. New O2 sensors(NTK), Map sensor, and checked for a vacuum leak and I still get the code popping up. Will run and idle great for a while and then the issue happens again.
Any help is appreciated, thanks in advance!

 

[AndyG]

Keep an eye on here..I don't know the answer , but we have some members that likely will.

Good knowledge here.

Andy

 

[Cross-Threaded-06TJ]

Sorry for the double posting, I realized I added this in the wrong forum too late.

Thank God for Jeep forums, I'm at a loss.
I'm in no way a mechanic, but can handle minor jobs.. my 99 4.0 was idling rough intermittently, and I cleaned the throttle body/ IAC sensor/ and replaced the TPS sensor. After that I got the Bank 1 Lean code for the first time.
Mine is older (had for a couple years now), and I dont know what has or hasn't been done- so I figured some sensor changes couldn't hurt, even if not the exact issue. New O2 sensors(NTK), Map sensor, and checked for a vacuum leak and I still get the code popping up. Will run and idle great for a while and then the issue happens again.
Any help is appreciated, thanks in advance!

Check for a crack in your exhaust manifold, especially around the front 3 cylinders "bank 1".

If its cracked it can cause this issue.

 

[twistedlv]

Download your FSM Here. It will have troubleshooting advice.
But I also agree with the two previous posts.

Edit: I just reread your post. Did you remove the throttle body to clean it? If so, did you use a new gasket and torque properly on reinstall? When I did mine the gasket looked fine, so I reused it. Only much head scratching and a smoke test revealed that is was not.
4 bucks at o'rielly's and I was back in business.

 

[Chris]

Use an OBDII scanner to reset the code and see if it comes back. If it doesn't come back, it was just a fluke.

Happens to me from time-to-time, that's why I always start by clearing the code first, just to see what happens.

 

[Airparis33]

Thanks for the replies yall, it keeps coming back sadly.. gonna try and check the manifold tomorrow. Woke up this morning to it having been broken into alongside our other 2 vehicles. Wild start at 4am lol. Also thanks for the manual link! Now I may can fix my washer fluid too

 

[Jerry Bransford]

Disconnect the battery's negative connector for 3-4 minutes to reset the computer, then securely reconnect it. That will put it into a re-learn mode for those changes you made. See how it runs a day or two after doing that.