peejer

I have a 98 Cherokee Sport 4.0L Straight-6 Automatic.

Problem**
Jeep starts and idles at low RPMs, sputters and will sometimes stall. Tapping the gas sometimes straightens it out for a minute or so. Hesitates, sputters and pops under the hood at low RPMs. Again, letting off the gas and then tapping the pedal a bit will usually straighten it out and then it drives fine.

It will sometimes surge/lunge forward while having it's fit.

I have replaced the TPS, plugs, wires, dist-cap and rotor, fuel strainer and both O2 sensors.

The problem is still with us. Any ideas? (good ones)

Thanks, John

sthon

I would check for vacuum leaks next, maybe clean the IAC as well.

peejer

I don't hear any vacuum leaks but will check again. What's an IAC?

Thank You.

sthon

Idle air control. https://www.cherokeeforum.com/f30/ho...le-body-76947/

Cheap and easy place to start.

sthon

Hmm, pictures no longer workie. Try this one. http://www.jeepforum.com/forum/f9/cl.../#post10277503

peejer

It wasn't the IAC. Looked darn near good coming out. Looked great going back in. Didn't fix my hesitation, sputter and lunge.

Next to try??

Thank You, John

peejer

Still not running right. Still the same symptoms.

List of replace parts:
Champion Plugs
Wires
Dist. Cap & Rotor
Throttle Position Sensor
MAP Sensor
Fuel Strainer
Fuel Filter/Regulator (Combo)
Catalytic Converter
Muffler
Up-Stream & Down-Stream O2 Sensors
---

Have cleaned throttle body (inside and out while removed from intake)
Have cleaned up an already good looking Idle Air Control Valve

I even decided to replace a fuel line while I was down there. She's still acting up at low RPMs. Sputters, may pop under the hood, may suddenly lunge forward with a surge of power when sputtering.

Where do I go from here?

Thank You,
John

NuclearCowboy

Any loose or bad connectors?

letinsh

I assume you did, but when you replaced the TPS, you adjusted it properly, correct?

Kalali

Where .did you get the TPS from? Some aftermarket Chinese units have been problematic. When it comes to sensors its best to spend the extra few $ and get a Mopar unit. DAHIK

bwebb

hey Peejer
anyluck yet mine has started the surging at stoplights and chugging. Then today it was
what sounded like popping or backfiring. Had the radio to loud so missed what really happened.

peejer

Found out that the up-stream O2 sensor (replaced 6 months ago) was not working properly with my computer. It's an aftermarket sensor from a local auto parts store. Nothing wrong with the sensor other than my jeep doesn't like it. Guess these problems all started shortly after replacing it due to the old one actually going bad. A jeep garage hooked it up to a monitor and waited for it to act up. They said the voltage coming from the up-stream O2 sensor is making the computer send a lower than required amount of fuel to the injectors. replaced the sensor with an OEM and it's running great.

BotakBeng

Thx for the update!

peejer

No problem. Hopefully it saves someone else $600 in parts and 20 hours labor....

On the upside, Peej is doing well. Running better than she's ever done for me.

Thanks for the help guys.