Jeep is stalling while coming to a stop

[RichTJ]

I recently just bought this 1999 Jeep Wrangler tj 2.5, knowing It hand some problems. I just had the transmission rebuilt, new spark plugs and wires. just took a look at the throttle body and IAC sensor both looked pretty clean.

It usually only stalls when the engine is cold coming to a stop or right when I start it up the idle while fluctuate and go low and sound like it wants to stall.

 

[LATJ]

My 2.4 did the same, cleaning the IAC fixed it. But that might not be the case for you since you've already looked at yours. Maybe give a good scrub anyway and all of the passages around it?

 

[Jerry Bransford]

A dirty IAC (idle air controller) would be my first thing to check too, that is what provides all of the engine's air at idle rpms. You can't see the part of the IAC that works by just looking at or into the throttle body.

Buy an aerosol can of throttle body cleaner and after removing the air intake tube from the throttle body and starting the engine, start spraying the cleaner into the throttle body at IDLE rpms. Don't raise the rpms up off idle or the cleaner won't pass through the IAC. The engine will die each time you spray the cleaner into the TB at idle rpms but that's ok, just restart the engine and do it again. Try to get 1/3 of the can through the IAC at idle rpms.

It is tempting to raise the rpms while spraying the cleaner into the TB to prevent the engine from dying but don't, that would cause the cleaner to bypass the IAC. Once you have at least 1/3 of the can of cleaner through the IAC then you can empty the rest of the can into the TB while the engine is running to clean the rest of it. Wipe/clean under the valve plate too, that will normally be black from combustion gunk.

 

[TheBoogieman]

I recently just bought this 1999 Jeep Wrangler tj 2.5.
It usually only stalls when the engine is cold coming to a stop or right when I start it up the idle while fluctuate and go low and sound like it wants to stall.

After checking the above stuff, have the battery checked.

 

[RichTJ]

My 2.4 did the same, cleaning the IAC fixed it. But that might not be the case for you since you've already looked at yours. Maybe give a good scrub anyway and all of the passages around it?

Sounds good I’ll have to give it a try.

My 2.4 did the same, cleaning the IAC fixed it. But that might not be the case for you since you've already looked at yours. Maybe give a good scrub anyway and all of the passages around it?

shoot I might have to. I didn’t take the throttle body off so that is next as well to clean it. The IAC looked aftermarket so maybe that could be the problem that it’s not Mopar?

 

[RichTJ]

A dirty IAC (idle air controller) would be my first thing to check too, that is what provides all of the engine's air at idle rpms. You can't see the part of the IAC that works by just looking at or into the throttle body.

Buy an aerosol can of throttle body cleaner and after removing the air intake tube from the throttle body and starting the engine, start spraying the cleaner into the throttle body at IDLE rpms. Don't raise the rpms up off idle or the cleaner won't pass through the IAC. The engine will die each time you spray the cleaner into the TB at idle rpms but that's ok, just restart the engine and do it again. Try to get 1/3 of the can through the IAC at idle rpms.

It is tempting to raise the rpms while spraying the cleaner into the TB to prevent the engine from dying but don't, that would cause the cleaner to bypass the IAC. Once you have at least 1/3 of the can of cleaner through the IAC then you can empty the rest of the can into the TB while the engine is running to clean the rest of it. Wipe/clean under the valve plate too, that will normally be black from combustion gunk.

I’ll give that a try. Thank you!

 

[RichTJ]

After checking the above stuff, have the battery checked.

I’ll have to check it out. Has a 2018 sticker on it as well. Thanks!

 

[rasband]

I used Jerry’s method before, and it definitely cleaned a bit. But a few months later while I was still having issues I yanked the whole throttle body and all sensors to clean them individually - it removed a lot more carbon buildup that it’s at least worth a try.

Unfortunately for me it was something else, but it is nice knowing that’s all reset to close to clean.

 

[elcaminoking501]

I used Jerry’s method before, and it definitely cleaned a bit. But a few months later while I was still having issues I yanked the whole throttle body and all sensors to clean them individually - it removed a lot more carbon buildup that it’s at least worth a try.

Unfortunately for me it was something else, but it is nice knowing that’s all reset to close to clean.

What ended up fixing it? Or still chasing the issue?

 

[rasband]

What ended up fixing it? Or still chasing the issue?

PCM replacement from @Wranglerfix .

 

[ChasUGC]

Did you ever check it for codes? Those are normally a good sign for the problem.

 

[elcaminoking501]

Im having the same issue. 97 4cyl Runs fine with a/c off. Turn on a/c it runs rough at low rp or idle and dies. Happens at random both warm and cold. No cel or other obvious issues. Just replaced a/c comp a few months back still free spins with no drag when engaged. Just did the carb trick today so hoping it will work.