hi guys,

i'm brand new to the site (as a member) but have spent numerous hours here reading all of your threads as i've worked through various issues with my 98 cherokee sport (all stock).

so, have any of you had the all too common issues with idle stuttering, racing at idle and in drive, and bogging to the point of almost cutting out? i had the same issues and finally found the solution a year later!! UPSTREAM 02 SENSOR-you believe that??!!

heres what my problems sounded like: the jeep would start, then after like 30 seconds start to idle hard. the rpms would drop really low and the engine would chug real bad then all of the sudden race up as if someone just floored the pedal. this would happen for about 3 or 4 minutes then stop. if i tried driving it during this stuttering the jeep wouldnt accelerate. if i was sitting at a stop light with my foot on the brake, the jeep would idle super low, then race up and if i wasnt pressing the brake hard enough the jeep would surge forward!!

so this is what i did: replaced spark plugs and wires, air filter, oil change and sea foam--nothing! then went to sensors, did the infamous idle air control motor (AIC), TPS, MAC sensor, coolant temp sensor (even broke the thermostat housing during this so had to replace that and thermostat--be careful!), crank position sensor, cleaned throttle body, checked distributor and such----all nothing!!!! i was so discouraged!!

i finally gave up because, even though the idle issue was everyday, it didnt bother the jeep not one bit after those initial 3-5 minutes of stuttering and almost cutting out. but one day while driving i must have hit something in the road and it ripped out my downstream 02 sensor. before attempting to replace it i decided to read up on 02 sensors and just replace both of them. well, i put the new ones in and no stutter--never again!! my problems for over a year were all gone!! the only thing was i had a CEL for the 02 sensor. i checked my wires and fuses and what would u know...it was the fuse under the hood for the 02 sensor heat element.

guys, all my idle and stuttering problems are gone!! all because of a freakin 02 sensor!!!!

sorry for the long post...hope this helps someone!

steve

 

Good info. Welcome to the site

 

Ive had some rough idle problems recently. I happen to have an extra o2 sensor that im going to put in ASAP. Hopefully it helps!

 

How old was the original and what brand did you use to replace? I'm having some rough idle and poor gas mileage lately and haven't been able to resolve.

 

So as i looked around the engine and took off my CAI i realized i had a loose vacuum line. Reconnected it and wallah shes back to normal aside from my ingition issues. I ended up returning the oygen sensor.