My 1999 4.6 Thor RR had developed a misfire. Put it on Techmate and ended up with new O2 sensors (two lots - the first were pattern and didn't work properly), plug leads and coil pack. It starts fine but has a horrible flat spot. Every search on t'internet points to the MAF but Techmate says everything is ok, including the MAF. Really stuck now. Can anyone help please?

thats how mine started with a flat spot at the lower end of the revs...now wont run at all, be interested to find out if it is your maf coz minesays its ok..

Is it a flat spot or misfire? If it is a flat spot it may be the TPS. If it is a misfire, it may be the coil.

What readings are you getting from the MAF ? I have some known good one somewhere that it may be handy to compare too.

It went to the garage with a misfire/lack of power. It was put on techmate, all faults cleared, and it showed O2 sensor problem. Changed both. Still misfiring/rough . Checked the spark and 2 were weak. New coil pack fitted. He noticed the plug leads were brittle so changed them as well. Still running rough. 2 more (OEM) O2 sensors fitted. No misfire but a real flat spot when revved hard and road tested. Techmate real time data shows everything "white",no misfires, O2 sensors doing their thing and "good" readings from the MAF. Can't remember what the readings were. He has now gone on holiday so I can't access Techmate data.