Hi all,

I bought a 2000 XJ Cherokee Orvis (UK) 4.0 litre auto last week with 150,000 on the clock.
Excellent service history and in good condition.

However, I've been driving it for short distances (6 miles every other day) and I've found that it has a engine hesitation / misfire issue (I'm not sure what the difference is between a hesitation and misfire so I've referenced both).

For example, this morning on the way to work it actually stalled for the first time. And when stationary in traffic I could tell that the engine was struggling against stalling and when I put my foot on the accelerator the revs would occasionally die but if I put my foot down the car would come back to life again.

It wasn't that bad on the way home from work and I've just been out in it tonight and it was ok.

I did notice that on the service history this issue started at 128,000 and the owner was quoted for a new engine ecu and 2x lambda sensors (by a none Jeep garage), but I've got no record of these being fitted.

The misfiring issue emerged again at 140,000 on the service history and a new plug lead set was fitted and the spark plugs were cleaned.
The spark plugs were cleaned again at 149,000.

The car hasn't failed on me...yet...so if it's just an annoyance I guess I could put up with it as I really don't want to spend anymore money on it at the moment.

Any advice would be most appreciated.
Please note that I don't know anything about the mechanics of cars when you reply :-)

Many thanks

 

What you describe sounds a lot like just a marginal battery, maybe a throttle position sensor but start really simple and go from there. Have your battery tested (not sure how things are set up over there, but most larger auto parts stores test for free here) and see what the results of the load test are. I had an issue very similar and it was just my battery, after me insisting it had to be more than just that lol.

Just for giggles if you have another battery, try throwing that in and see if you have the issue still. Can't hurt and gives other people time to add their input

 

can of throttle body cleaner idle air control valve is probably dirty as hell pull intake tube clean with spray and a rag

 

x2 that can never hurt and is quick and improves idle even if that isn't your issue!

 

Excellent, thanks.
So get the battery tested and clean tube (my Haynes manual is on order so once here I'll know where that is lol!)
Do you think the Lambda sensor is a red herring?

 

I have no idea what a lambda sensor is, and I have never heard the term red herring. Is that like a red flag?

 

Must be a British saying, it means that you're looking in the wrong direction / looking for the wrong fault.
The lambda senor I think is known as an 02 sensor in the US.

 

Ok that makes sense lol. I was reading english but not one thing was processing as a language I was familiar with

 

I drove it to work this morning (only 3 miles) and the same thing happened, came to my first roundabout and the jeep lost power when I pulled away but when I increased the accelerator it took off and was ok again. If this is an 02 or CPS sensor can I buy these online?

 

well sir, you are correct about the Lambda sensor, it is the O2 sensor, the chugging tho might not be a CPS, as on mine when the CPS went, or even when it started to go out, the jeep just shut off, no gurgling or low idle nothing, just off.

so it may be something to do with the TPS (Throttle Position Sensor), the MAP sensor( Manifold Air Pressure...a.k.a. Manifold Atmospheric Pressure sensor). Or even a split or cracked vacuum hose on the engine ( this can be easily visually checked with a STRONG flashlight, a spraybottle of water, just mist on the hose you want to inspect with the jeep idling and see if you have bubbling occuring, then you know you have a vacuum leak). Most jeeps have the emission/vacuum diagram on a label under the hood.

when was the last time the fuel filter was changed?

Are you 100% sure the spark plug gap is correct? (methinks .035in is the correct gap).

also have the fuel pressure checked, in case none of those suggestions seem to clear issue. might be bad fuel pressure regulator, or bad delivery from pump, depending on reliablity of your petrol stops (i.e. quality of fuel).

just some pondering ideas for you sir!

cheers!

cpnwrench

 

Oh yeah, forgot to tell you, yes you can buy on line


www.rockauto.com does ship intl.


cpnwrench

 

Thanks for your help, I guess the big question is...should I continue to drive it or could it fail at any time?

 

My advice is fix it, or get it fixed soon. problem may get worse , then you are stranded.

Seriously though, take a look a the simple things mentioned previously, they are FREE to do. And don't take a whole lot of time on your part to perform. Besides, you will learn something about the wonders of JEEP!

However, it is your decision and yours alone what you intend to do.

As John Wayne would say...."you can lead a horse to water, but he still wont get you a beer!"



cpnwrench

 

I had the same problem with my 99 cherokee sport. It eventually developed another problem of not shifting out of first gear (auto transmission) as well as higher rpm's at idle than normal. The problems were cured by replacing the throttle position sensor. Costs about $40 and 5 minutes to replace.

 

So this morning I've run the self diagnostics test using the trip switch on off x3 times method.
And NO codes were displayed.
Does this mean that the computer hasn't detected a problem or that there isn't a serious problem at all?