Hi! I'm a newbie on here and looking for some advice.

I have a 1998 Jeep XJ Cherokee (petrol) 2.5ltr - we've been having a jolting issue when driving, so we've been eliminating what could be causing it. The car itself is driveable and mostly runs smooth, but in low gear it feels like theres a misfire or connection fault that jolts the car. So far, we've been troubleshooting all of the mechanical issues that it may have, as such, we've put all new spark plugs on, a new temperature switch, new coil pack, new oil filter and had the front lander oxygen sensor unit replaced. At this point, it's been suggested that it's the ECU. We've spent a fair bit on the car already so would appreciate any knowledge/advice before we get an auto-electrician to look at it.

Thanks in advance!

 

Have you ever cleaned the throttle body?

It has no distributor? You mention coil pack. I know the export models were different from ours in certain ways.
If it has a distributor, make sure you replace the plug wires, cap and rotor.CRUISER'S MOSTLY RENIX TIPS

THROTTLE BODY AND IAC CLEANING

OCTOBER 30, 2015 SALAD 24 COMMENTS
Originally by TJWalker of CherokeeForum & JeepForum



The Idle Air Control (IAC) is mounted on the back of the throttle body (front for ’87-’90).

The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is retracted, the air control passage flows more air which raises the idle speed. When the valve plunger is extended, the air control passage flows less air which lowers the idle speed.

Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea. This should be part of a normal tune-up procedure and whenever idle/stalling issues are present.

CLEANING THE JEEP 4.0 IDLE AIR CONTROL

1. Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a Torx driver (2 bolts; one can be kind of hard to get to). On ’91 and later, it may be easier to just remove the whole throttle body. Be sure to use a new throttle body to manifold gasket when reinstalling.
2. “Gently” wiggle out the IAC from the throttle body. Gasket/O-ring on the IAC can be re-used if it is not damaged
3. Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and oxygen sensors. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.
4. Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner.
5. It is also a good idea to clean the entire throttle body bore itself, the butterfly valve inside of the throttle body and it’s edges, and all associated linkage as long as you have things disassembled.

Revised 1-31-2016

 

hi,i cleaned my throttle body yesterday took it apart completely to clean it (nothing wrong i just thought i would clean it) took the throttle plate out to clean it,also the IACV mount it was dirty but it cleaned up well,took the throttle plate shaft out and cleaned the bearings and re-greased them put it all back together and back on the engine,runs lovely..so well worth doing,good luck.

 

I need to ask what that means...

 

Yeah, I'm curious as to whether I want to experience that...

 

Fluff? This comes to mind.

 

I've not yet cleaned the throttle but will try that before handing over to the auto-electrician. Thanks for the help!

 

LoL.
Well the OP has edited post#1;
The fluff part was code for "a misfire or connection fault".

 

Great idea.