Well that was "interesting". Went the long and expensive way round but finally sorted.
Turned out to be throttle cable adjustment being way out. As it has been in all 11 years I've owned the car. It always seemed to run OK so I never bothered to check the setting it arrived with, basically 3/16" free play with the adjuster close to the end of its travel. With it that far off book I guess the MAF and TPS, which according to RAVE has an important part to play in setting fuelling all through the range, were barely on the same page and drift over the years finally put them at odds.
After ordering a MAF from Land Rover Direct on the 7 th, because the Island 4x4 site, wasn't working for me, I decided to try things with the throttle adjusted up as far as it would go. Still 1/8" play but I was able to get a kick-down with full blooded stamp on the accelerator. As I had a new cable in stock and the one fitted was out of adjuster travel I decided to change the cable.
2 days of struggle swearing and trying various things finally got the old one out. If I ever pull another one out I shall immediately cut the inner cable and chisel off the end of the rubber sleeved plastic thingy inside the car. With the knob on the end gone a few swift taps with the special offset drift I welded up for the job pushed the thing out far enough to grab on etc outside easy as could be. Given how impossibly stubborn mine was initially I expected to find the support tube in the body corroded to hell and gone. In actuality it was perfectly smooth. I reckon the difficulty of removal is due to the knob on the end of the plastic bit swelling the rubber ridge sitting on the inner end of the bulkhead support so much that no power on earth will pull it through.
New cable went in easily. I used red rubber grease rather than the RAVE approved liquid soap. Persuading the little plastic bung to go into the hole in the accelerator cable took another half day of braille manipulation. If you don't get it right first time it's fatally easy to spread one of the prongs a little bit. With predictable results. I found it best to tape the other end of the cable up to compress the boot to its minimum length so there was some excess cable inside permitting free movement of the plastic bung. Wooden block under the accelerator pedal held it out of the way at bottom of its travel. No way that I found to stop the pedal going up the left sleeve of my overalls every time I moved.
New cable had just enough adjustment to get the gap between cable selector and actuator down to about 1 mm. Leading me to think it was a pattern cable.
Bonnet shut, interior plastic re-fitted, tidying up nearly done when the penny dropped. RAVE shows the cable bracket running straight up and down. Mine was at an angle leaning towards the throttle actuators. Surely the bracket holes aren't slotted. Diving under the bonnet again and making with a spanner proved they were slotted. Setting the bracket vertical restored the cable adjustment to something sensible with the RAVE specified zero gap between cable and acutator.
Which I could have done in the first place if I'd gone back to first principles and verified all the set up rather than assuming "it was OK, now something has gone wrong". Considering thats the first thing I do with someone else's problem its distinctly hoist with my own petard. Sigh.
Quick test run shows car is now much more lively than it ever was and the gearbox much more responsive to the throttle. It always seemed to drive decently before but very much non sporting. As I expected from a softly tuned V8 in 2 tons of permanent four wheel drive car with the aerodynamics of a shed. Seemingly effortless 80 mph motorway cruise was clearly deceptive.
Just to make a bad weekend and start to this week worse the poxy SRS light has come on. Double checked any connections that might have gotten disturbed to no avail so hopefully it's an intermittent issue returning after 5 years.
Foam in the heater duct joints had gone so I used some self adhesive ribbed door/window sealer got from LiDL a year or three back 'cos it might be handy. Just the job. Before fitting I went round the ends of the duct with duct tape leaving about half the width upstanding. 8 snipe cuts, two at each end of the corners, let me fold the tape down over the draught sealer so things didn't get caught up on the edges of the other parts of the duct. The duct slipped in so easily that I had to look three times to confirm it was in.