lumpy engine

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yewtree

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i have had my 3.7 petrol kj 04 reg for just over 2 weeks now and the engine runs a bit lumpy on just above tickover and when pulling away, as soon as it get to between 1200-1300rpm it runs as smooth as can be, it is just like a misfirs, i have changed the plugs and done an engine flush, new 5-30 oil and new filter, any help would be great

thanks phil
 

ChiefRudy

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when idling the 3.7 does give a little rumble every few seconds. I feel it best in lower back of seat. It's normal far as I'm concerned since my fathers 05 liberty does it and so did my wife's 02 liberty.

however. I never have an issue pulling away. If it feels like the engine stumbles at the beginning of take off I would check air flow sensor. Make sure it cleans.
 
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02blue

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when idling the 3.7 does give a little rumble every few seconds. I feel it best in lower back of seat. It's normal far as I'm concerned since my fathers 05 liberty does it and so did my wife's 02 liberty.

however. I never have an issue pulling away. If it feels like the engine stumbles at the beginning of take off I would check air flow sensor. Make sure it cleans.

Agreed. Make sure the air filter is clean and maybe run a bit of injector cleaner through it. I like the Techron if you can get it over there.

BTW, Pittson Pa, right on the mighty Susquehanna. Small world, I'm a Scranton native. I really miss all that good pizza.
 

Birdman330

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Having driven now both Automatic and Manual KJ's I've noted the Manuals are big more rough when it comes to idle and take off than what automatics are.
 

Snail Farmer

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Having driven now both Automatic and Manual KJ's I've noted the Manuals are big more rough when it comes to idle and take off than what automatics are.

Hmm, not sure about the ones you drove, but mine is a manual and it idles extremely smooth, and it's always been smooth and strong on take off. (of course it's broken right now)
 

Birdman330

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Mine is rough and as I call it grumbles even with the new driver side Cat and 02 sensor and I have driven a couple manuals that have come through the drive, not as rough as mine is but I also wonder if it has to do with my clutch. The individual in the Military that had it before me put in an aftermarket clutch which is stronger than the stock clutch. So my clutch pedal is twice as stiff as stock, I have not driven another Libby with a clutch pedal as still as mine.
 

LibertyTC

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Rough idle etc comes from not keeping the ole girl's intake etc clean too.
Remove the hose attached to the intake, get some throttle body cleaner and spray some into the intake until it looks shiny & new!..
Then it's onto the IAC & associated ports...carbon gone = Jeep Happy!
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I clean the IAC & Throttle plate/intake every year now. It needs it.
Also check that the air filter & box & sponge bob is clean & check the PCV Valve too!
 

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yewtree

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Rough idle etc comes from not keeping the ole girl's intake etc clean too.
Remove the hose attached to the intake, get some throttle body cleaner and spray some into the intake until it looks shiny & new!..
Then it's onto the IAC & associated ports...carbon gone = Jeep Happy!
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I clean the IAC & Throttle plate/intake every year now. It needs it.
Also check that the air filter & box & sponge bob is clean & check the PCV Valve too!

thank you very much, i am of the motor factors right now to get carb cleaner and do everything you have explained, will let you know the outcome later.

thanks phil
 

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yewtree

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after doing all the cleaning of the air intake and throttle body i noticed this
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aftre cutting all the tape off this is what i found

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i guess this didnt help things at all

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runs very much smoother now, thanks for all the advice

phil
 

ChiefRudy

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Agreed. Make sure the air filter is clean and maybe run a bit of injector cleaner through it. I like the Techron if you can get it over there.

BTW, Pittson Pa, right on the mighty Susquehanna. Small world, I'm a Scranton native. I really miss all that good pizza.

Small world it is. I wouldn't be able to live with out my NEPA Pizza.
 

02blue

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Small world it is. I wouldn't be able to live with out my NEPA Pizza.

Still visit often enough to quench the pizza cravings, Old Forge has some good pies. I remember spending lots of time at the old Staircase Lounge too.

:emoticondancer:

I never could dance worth a sh$# though
 
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