Stalls When Revving

JeepBeat · **Posted:** Thu Apr 16, 2009 7:26 pm

I have owned my 2002 Liberty for two years, and never noticed this. As a rule, there is never a need to rev the enging when idling. My Jeep starts great and runs perfect. Today, for fun, when in park, I revved the engine just a bit. When the RPMs came back down to idle speed, it stumbled, then stalled. I restarted with no problem and it idles fine. Any ideas why this would happen??? Never a problem with it. Might the plugs need to be changed out, or something maintenance wise that may make it run better? Just curious. Thanks.

tjkj2002 · **Posted:** Thu Apr 16, 2009 8:59 pm

Sounds like carbon build up.Slowly suck a can of SeaFoam through the vacuum line that run from the engine to the brake booster(take the booster side off and dip in can),you will need to do it slowly and keep revving the engine to keep it from dying.After the can is dry shut off,reconnect the vacuum line,wait about 10-15mins and restart and watch the smoke show.Let the engine cool and change the plugs,Autolite Platinum's seam to be about the best for the 3.7.

ATXKJ · **Posted:** Fri Apr 17, 2009 1:45 am

How old's the battery?

on the Liberty - you have to have enough voltage to keep the computer on - even if you have enough current to start it - it won't stay running if the battery doesn't have the voltage.
(rev'ing the engine would increase alternator output)

Guest · **Posted:** Fri Apr 17, 2009 2:53 am

BOTH OF YOU ARE WRONG!!!!

This stalling is a sign of a Hemi and SFA swap as scheduled by the owner's manual!

Trust ThunderbirdJunkie, it's in the fine print;)

sleeve84028 · **Posted:** Fri Apr 17, 2009 9:43 am

Could that not be caused by a small vacuum leak? [Just asking, I am not suggesting this is the problem]

JeepBeat · **Posted:** Fri Apr 17, 2009 10:36 am

What is Hemi and SFA swap?? What about vacuum leak?? What would I look at??

To the battery question, I think the battery is original from 2002.

Thanks for any more help you guys can offer......

sleeve84028 · **Posted:** Fri Apr 17, 2009 12:15 pm

The SFA swap is more of a joke [SFA = solid front axle]

The Hemi is a reference to the tiny engine in the Liberty [Stock - 3.7L versus the Hemi @ 5.7L] Please note that no one has done a hemi swap into the KJ.

My question about the vacuum leak was more of a general question and does not suggest that your KJ is suffering from a vacuum leak at all.

Change the battery for sure. The KJ battery in 2002 is undersized and your is probably on it's last leg. Try to find a Optima Redtop [you can search the forum for the correct size]

And then follow TJ's recommendation for the SeaFoam. I did a seafoam on my 2002 (city driving) last year and it didn't get too smokey but the change in performance was worth it.

JeepBeat · **Posted:** Sat Apr 18, 2009 11:52 am

what is Seafoam?? I live in Canada, is this the actual name of the product?? Where do I purchase it? How hard is it to administer? Thanks.

JeepBeat · **Posted:** Sat Apr 18, 2009 11:53 am

what model of Optima red top do I look for, to put in the 2002 Libby?

JeepBeat · **Posted:** Sat Apr 18, 2009 1:52 pm

hey guys, just bought a can of Seafoam at my NAPA auto parts store. Can anyone tell me (being a rookie) where to unclamp the PCV valve. Can anyone show a picture?? It says to pour 1/3 of the can into the intake, as you suggested, then shut off for 5 mins before restarting the engine. I just want to pour this stuff into the right place. any help is appreciated. Thanks

Diggerfreek · **Posted:** Sat Apr 18, 2009 3:29 pm

tjkj2002 wrote:

Sounds like carbon build up.Slowly suck a can of SeaFoam through the vacuum line that run from the engine to the brake booster(take the booster side off and dip in can),you will need to do it slowly and keep revving the engine to keep it from dying.After the can is dry shut off,reconnect the vacuum line,wait about 10-15mins and restart and watch the smoke show.Let the engine cool and change the plugs,Autolite Platinum's seam to be about the best for the 3.7.

Just do what tjkj wrote and you will be fine. you don't want to pore in on to the engine like you just wrote

ramlebliberty · **Posted:** Sat Apr 18, 2009 8:37 pm

could also be the tps. My kj would start and idle fine, if i hit the gas it would rev then stall, also stalled one in a parking lot when i was pulling into a spot giving it a quick rev.

do the sea-foam - cheap
have your battery tested - free
if all else fails check for a tps error code by turning you car on & off 3 times. code is po0122 -123 i believe

Stalls When Revving

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