have a friend with a 97 cherokee 4.0 4wd auto.
he has been complaining of it running rough idle spiratic and smell of unburnt fuel when it is warming up. replaced plugs wires cap rotor tps iac temp sensor cat 02 sensors and nothing has fixed it was thinking vacuum leak but all hoses are new and im stumped not to mention he is now low on cash after replacing everything else what could it be ?

 

sounds like a jeep.

mine always runs better, when the water in exhaust is blown out after cold start .. sometimes I'll rev angine a bit .. to spit it out quicker

 

down fall is when i say cold its when its the most low of 45 outside and has been sitting so engine is cool not like we deal with freezing or lower here in tucson,az and it will run like that until it reaches normal operating temp but he recently has had issues even after it reaches normal operating temp

 

check battery ground .. I chased a similar gremlin for 3 years .. thought it was what your describing too .. changed alot of stuff out

my neg battery cable was oil soaked, rotten .. bad

I changed that .. gremlin gone ! just a thought



Someone else should comment on that though .. I dont know the 97+ very well , as far as where / what grounds they have

 

Clean grounds really well, battery, block rocker cover to firewall. Clean em all, no cost and can't hurt. I ran extra ground to the front fender and extra to block, never ran better and cured some significant hickups. All takes is less than hour time.

 

another one? this is like the 4th one this week. same thing happend to mine. i cleaned idle air control and it didnt help so i cleaned all my grounds/battery terminals and it is running just fine. do you people even search?

 

Can you be more specific and can you post pictures? Thank you.

 

im sorry i didn't search my bad i did do a google search though and came up with nothing so i asked on here. i will check all ground wires/ connections and i will give an update thanks guys for everything. you never let me down

 

been a bit but did find the problem hair line crack in gasket under throttle body thanks for your help again guys

 

Glad you fixed the problem. My suggestion was going to be disassemble the TB and check the MAP, and you would've noticed that


For what it's worth add "site:cherokeeforum.com" when you look on Google. That keeps the results here and ignores the BS from Yahoo Answers for Grand Cherokee lol.

 

Did you just buy a new throttle body gasket?
How did you find the cracked gasket?

 

you buy a new gasket they are not reuseable...

 

yeah bought a new gasket found it by having my buddy start the jeep and i just sprayed some tb cleaner around vacum connections and at mating surfaces of intake to head just to see if there was a difference in idle and when i sprayed base of tb it ran smooth for a second or so. found out that my buddy had taken his tb off previously and cleaned it but never replaced gasket cause it was " fine" i felt like smacking him after that but another jeep fixed

 

thank you i never thought of doing that will do this in the future for sure