4.6 v8 range rover running lean?

Hi guys i have a 2001 4.6 v8 with a bit of a nasty engine problem. Basically ticking over there is a slight miss fire. But when you press the accelerator the engine boggs down, then slowly builds up and then sounds fine again. Also on driving it is completely gutless as in unusable. Being a mechanic i have done all the usual things compression test etc and all seems fine. No engine management lights on but decided to plug in, and the emissions are pretty much zero and it is running very lean.

Quite puzzled by this any help would be much appriciated. Thanks

I had the same problem with mine mate a while ago and it turned out to be one of the O2 sensors

I replaced both at the time and sorted it

Scott

The misfire will be the cause if the oxy sensors are working - it will see the unburnt fuel as a rich signal and try to lean off the mixture even more.