Cleaning the MAF on a Disco 2 is a last resort, right before you order a new one. And it should only be done dead cold. They really don't take well to cleaning, and it may not work at all or make the problem worse.

Your O2 sensors are not used at all on cold starts, so that can't have anything to do with your issue.

 

I also have a P0150 code now too - O2 sensor....

 

The P0105 / P0171 / P0174 codes seems that they could be a symptom of reduced engine aspiration, from all I read.... All those cases where someone replaced O2 sensors just to have same O2 related codes....these are ubiquitous on these forums.

Maybe a can of Seafoam in intake and a can of BG44k in gas may help.

I have cleaned the MAF (yup, I know, but I have already ordered another MAF).

I have a theory that some water mist may have got into the intake and buggered up the MAF and intake??

 

This is my experience with MAF sensors and O2 sensors. My truck didn't have the stock air box on it and I went wading through some deep water, thus wrecking my MAF, it could not be cleaned (I tried it). It had to be replaced, and it was around $200 bucks. As for O2 sensors I had the bank 2 upstream air sensor go out. I ordered two from Amazon for $60 each and got the tool from O'reilly's for $9.99 (the offset one works the best on the Disco II imo). Because the driver side one is a real pain to get off I did just the passenger side one (the one that threw the code initially) at first. I did it with a cold engine and completely doused the thing with WD-40, tapped on it with a ball ping hammer a few times and waited about 10 minutes. It came off like butter. Installed the new one with some high temp anti-sieze on the threads and some dialectric grease on the plug. Then I cleared the codes and drove it around for about 15 miles code didn't come back. I didn't get to the driver side upstream O2 sensor for a week. My truck never popped another code but I religiously track my gas mileage and I didn't notice an improvement until I replaced the other O2. My suggestion is to get the right parts and the right tools the first time. Other vehicles seem more tolerant of shade tree mechanics but Landys don't seem to be. Just my two cents.

 

Seafoam in intake manifold and in Gas tank, and Throttle body cleaned out.

New MAF on the way. I cleaned original MAF and it is still working, but still difficult to start. Once running, runs fine (with codes)...

Anyway, if this doesn't do it I will order and install the two O2 sensors. The passenger side plug is going to be a bear to get at. Driver side did not look so bad...

 

Atlantic British is having a sale on O2 sensors until 8/31/11: Land Rover - Parts, Accessories and Information

 

Good deal on the O2 sensor ($59). I will order a pair as soon as I know the MAF doesn't fix the hard start and/or P0150 / P0171 codes...one fix at a time...

 

there are o2's 4 on your truck, two before the cats, 2 after. there are 2 cats, one for each side of the motor. they are all rather easy to get to on these cars, follow the wires on the back of the motor that go stright down to a thing sticking out of the exhuast pipes, there should be one on each side looking from the engine bay, these are the precat, or before cat sensors, or upstream... also they are "sensor 1"s... the "bank number" tells you drivers side or pass side (drivers side = bank 1, pass side = bank 2) and sensor number tells you front or rear (1 = before, 2=after cat) sensore 1 being before, sensor 2 being after or post cat, or downstream. the rears you can find by crawling under the truck they are simply further back on the pipes before they merge about midtruck.

running lean doesnt necessarily mean your o2s are bad, you COULD be running lean (for a number reasons), meaning there isnt enough fuel for the oxy levels in the combustion, the precat o2s detect this by sensing a high volume of oxygen, showing incomplete combustion. could be missfire or incomplete compression, headgasket or exhuast leaks, bad maf, bad injectors etc. the computer uses the coolant temp, the maf data, manifold pressure and a preprogrammed reference chart to decide how much fuel to use at a given engine load, then takes in account the data from the front o2's too see if its on the mark and then adjusts once warm. cold, it uses only the data chart and ignores o2 sensor input until they are of proper temp to get an accurate reading. the rear o2's are to test if your cats are actually still working, as the exhuast passes through them they scrub out the nasty stuff, so when the exhust gets to the rear o2s, the computer has an "after filtering" data to work with to see if you cats are actually still doing there job. gut your cats and the rear o2s start reading closer to the same pattern as the fronts, and bam, computer knows they ain doin thier job, and the fed gov says you can run like that and flags you a nice engine light to remind you that you are melting icecaps and killing baby kittens.

carbon fouling from unburnt fuel smashing into your hot o2 sensors reduces thier sensitivity, and starts screwing with thier data, which causes your computer to thing its fuel trim (how much or how little fuel its adding per "squirt" from the fuel injectors) is not proper. if you are getting intermitten or no data from the o2's, they may be shot, or in some cases, the harnesses are loose, burnt up from touching the exhust... or covered in oil from the oil leaks that these damn motors have all to commonly. you can try unplugging them at the sensor harnesses and cleaning them up good, and ziptying them out of the way from any oil slicks that are riding down the wire.

exhuast leaks from holes in the exhuast pipes, connections or blown gaskets also suck in air into the exhuast stream which also causes the o2s to read lean, since the computer things that there is too much o2 in the exhust, it assumes its a closed system, and any air getting to the o2s is comming ONLY from the combustion chambers.

you can also check the wiring, it happened to my 00 disco... the main harness along the back of the engine bay where the hood meets the windshield can short internally and rub, especially at the plastic clamps, in some cases, it might be enought to drop out entirely or cause intermitten data from one or MANY sensors, in my case, 3 of 4 o2's, the SAI and MAF all malfunctioned intermittenly because of a short wire rub where the pass side harness connected. simply removing the t clamp and jiggling around the wires broke the short and all the data came back alive and it ran fine afterwords.

as far as getting the engine light cleared, buy a cheap obd2 scanner to do it yourself (also great benefit to read your own codes in the future, which you will have alot of owning a LR haha) or bring it to a garage. the laws differ state to state, in some places its against the law for anyone but a certified emissions repair facility to clear emissions related codes. you can also pull the battery for a good amount of time to reset them, but if they are nonemissions, or still valid codes, the light will just come back on shortly after.

you do need a special tool to remove the o2 sensors from the pipes...most of the time anyway. if you have a good sized adjustable wrench you could probably do it, but i wouldnt recommend that headache, youd be screwed if you rounded the head on the o2 sensor. they sell sockets with slits in them to slip over the wire that connects to the o2 sensor... or you could buy a dedicated wrench with the correct size head. its basically just an open on both ends socket wrench that can slip around the wire. its just like removing a large spark plug. be warned, they can be VERY difficult to remove, especially if the pipes are rusted or old. sometimes it takes a break bar or slip bar over the wrench to get enough torque on them, sometimes it takes a torch to heat them up to soften the threads up to get them out. doing it this way will probably destroy the o2 sensore be mindfull, either by melting the wire or simply overheating the sensor itself.

good luck to ya! check your fuses, rubbed wired, burned wires and connections first, also all free and rather simple to do

ps. i think the connections for the o2s are bright orange? atlest they were on my disco, should be only thing down there with that color! they are about level with the oil pan in depth, you can reach the front 2 by hand from the side of the car down and behind between the wheel well and motor...youll see em, they are fairly obviousy being the only thing plugged into the exhuast other then the secondary air pipes which are right at the top basically.

 

Jesus, try writing with paragraphs and capitalization. Your post is nearly unreadable.

 

Usually I do, I was on my phone bored at work though haha! I'll edit it up in a few...