Keep us updated. I've replaced everything but the O2 sensors trying to fix my inconsistent erratic high idle. My O2's test good and don't throw any codes...in fact I have no codes at all anymore, but I still get 8mpg and have that stupid idle problem. Maybe I should check my base timing...see if my timing chain is slacking...

 

I have read a few posts from the other Land Rover forum and someone had all the same symptoms. He ended up changing everything almost and claims new O2 sensors cured his problems. Another post suggested an intermittant IACV. I can see the IACV causing problems with the stalling but for the rich mixture and bad fuel econemy I would have to say O2 sensors. Next weekend I'll be neck deep again, I'll let you all know what the results were.

 

Since you are able to warm the engine up, and the problem begins, even at idle or high idle.... could you take a can of spray brake cleaner and cool down each sensor one by one? That old TV repair trick might shed some light on the particular sensor, since you don't have a live data code reader where you can see the interaction between them.

 

Also if you think your issue is running rich etc. You only need to do the upstreams to effect mpg's. Will tillery had me out the door with some guaranteed good used ones (a pair) for the cost of roughly ONE ngk 25044 or whatever the part number is. Def reach out to the recyclers. Especially when you're throwing parts at something when you're guessing.

 

Savannah Buzz: That's interesting and definitly something I'll try. My thoughts are on the O2 sensors mainly because the rich, stalling engine condition occurs when the engine is warmed up. I'm thinking that the O2 heater elements are faulty. I had cut the wires a few months ago and wire-spliced in my spares. I'm thinking by cutting the wires, it somehow created a problem with the internal heaters. This would definitly throw off my engine.

 

Some of the vulture mechanics on branch 3 of the shade tree have suggested that we listen carefully to your problem statement:

On a cool morning, truck cranks, runs well, about 150 rpm too high, and makes the trip to the office with no problems. About two hours later, problems appear as soon as truck is cranked. What has changed?

The sensors ON the engine all originally warmed up, and made the trip. Now we don't know how far that was, but it should have been a distance that would allow warm up, otherwise he would jog.

There is a sensor that is off the engine, that would have been cooler at morning startup, and stayed cooler until arrival at the parking lot. After truck was turned off, that sensor would warm up above outdoor temp from waste heat given off by engine and sun light fading the paint on the hood. That would be the IAT sensor mounted in the air cleaner box. It is a simple device with a few holes drilled in the end of it for air circulation. Might be a place that has been missed, either for trash or insect nest, or just bad sensor (hose down with brake cleaner).

Now this is just a theory, and those vultures don't carry the same weight as the monkey with the 3 piece suit perched above them (that would be the Branch Manager).

 

When you swapped your other ECU in did you have everything reset by someone with Testbook? When I replaced my IACV and TPS my truck still ran like crap until I had everything reset. Just curious.

 

No never had any reset performed on my ECU. Is that an issue, I don't know. Who performs ECU resets? Is that Land Rover dealership's only? When I had the 97D1 ECU in the engine ran fine for a few months. Then som ething happened. This truck acts like it was hit by lightning or something. Just all of a sudden my MPG dropped to 7 and stalling at stops when warm. I put a scanner on it and it read downstream O2's. I found one on the passenger side that had exposed wires from rubbing on the drive shaft. I replaced both downstream with two spares from my 97D1. Then drove for a while and noticed black soot on the tailpipe and spark plugs. I put the scanner on and all the O2's were codeing and a misfire. A total of nine codes. I swapped out the CATS with my spare and swapped out the two downstream O2's once more. I cleaned the front O2's and put new rod bearings in. I changed out the ECU engine coolant temp sensor, oil pressure sensor, crank seansor, MAF sensor, air temp sensor, spark plugs & wires, fuel regulator and swapped the 97D1 ECU and put the 99D1 ECU back in. Still have all O2 codes and misfire.

 

Find an indy that can reset your adaptives and that will do the trick. I've been down this road and that's what solved it. Chris-bob was dead on with resetting the IAC without Testbook and when that method fails you have no other alternative but an adaptive reset.

 

That does require the LR Testbook does it not?