Hey everyone got a little issue with the LR3 that I wanted to see if anyone has had any experience with. My LR3 at idle and light throttle has developed a intermittent stumble/miss. This started a few weeks ago and since the LR3 had a little over 100,000 miles I decided to do a quick tune up. I replaced the spark plugs, cleaned the throttle body and cleaned the mass air flow sensor. This seemed to correct the problem, but a day or so ago it started to have the stumble/miss again. There has been no check engine lights and I am stumped as to what could be causing it. Is it possible that it could be bad gas? Filled up a day before this started happening again.

 

I hate those issues that come and go. Seem like you are chasing your tail more than chasing the problem.

How new are the air filter and PCV?
Have you looked for leaks in the intake tubing after the MAP? You may be getting unmetered air into the system.
What condition are the vacuum lines that are closest to engine? You may have a line that was moved and the small cracks sealed up until it returned to its usual position during normal driving.
How are the vacuum connectors that fit the intake tubes and throttle body? There is one on the back of the intake tube just before the throttle body and another one in the back of the curved part that connects the butterfly valve to the intake manifold.
What is the voltage readout for the accelerator pedal and throttle body? Refer to the service manual for the tolerances, it may need to be recalibrated.
What are the voltages on the upstream and downstream O2 sensors? This can affect the fuel trends.
What are the long and short term fuel trend showing? It may be showing a lean condition that is just short of triggering a fault code during first application of throttle. (does it stumble in the sand/grass mode as well?)

Try a soft or hard reset. Sometimes that fixes the calibration between the pedal and throttle body.
If it that does not fix it, you could try an adaptation reset for the transmission.

Just a “few things” to look at. Let us know how it turns out.

Jeff

 

I had a similar issue turned out to be a weak coil pack that eventually set a code. Replaced it and.been great ever since

 

Thanks Rufflyer and ArmyRover. I will look into those and update you guys on my findings.

 

In didn't think about coils, I was trying all of the free stuff first. but ArmyRover, you may be on to something with the coil. Problem is you either buy all 8 ($$$$$$$$) or buy one ($) and keep swapping until the problem goes away.

Either way, rhuca6, we will stay with you until you solve it. Keep us informed of your progress.

Jeff

 

Well guys last night on my way home the stumble/miss got quite bad and eventually threw a check engine line. Pulled the codes and I am getting a misfire on cylinder 7. Looks like I will be ordering myself a new coil pack!

 

Good to hear sort of lol

Rudflyer, I have a spare coil in the rear cubby. They really aren't that pricey

 

I replaced an ignition coil earlier this year due to a check engine light. Oddly enough, it was also on cylinder 7. I purchased the coil from the local Jaguar dealer, as it was actually cheaper than from the LR dealer. The part number is AJ810445. It looks slightly different than the original one that was on the LR3, but it is a perfect fit, and the CEL has gone away. I suspect it is made by Denso.

 

I ran across this list some time ago and copied it in case I needed to buy a coil. I can't verify the accuracy of the numbers or if they are the right size to even fit, but it is a place to start if you can't get an LR part while on a road trip. Of course ArmyRover has the best plan, buy one and keep it in the rear cubby hole (right next to your spare brake pedal switch and brake light bulbs I would guess)


MANUFACTURER---NO.
FORD---------------6R83-12A366-AA
JAGUAR------------AJ87 644
JAGUAR------------AJ810445
JAGUAR------------AJ83 415
LAND ROVER------474 4015
LAND ROVER------452 6466
BOUGICORD-------155247
DELPHI-------------GN10448-12B1
HuCO---------------133891
MEAT & DORIA-----10648
NGK-----------------48267
SIDAT---------------85.30484
STANDARD---------12442
C.I.------------------XIC8432
DENSO--------------099700-1120
FUELPARTS---------CU1329
LUCAS CAV DMB1112


Jeff

 

I can neither confirm nor deny anything, But you might be on to something