This was my next input, no familiar with these engines in particular, but how is the timing controlled via the coil packs, surly the ECU timing map does this? I was going to suggest a coil pack breaking down under load, although it should result in a misfire,
I would still test or substitute cam and crank angle sensors as this could have a big impact, and effect the function of the VVTI system.
Ok thanks, going to try and source an ecu from a breaker just to eliminate that, wont hurt to have a spare. Then move onto your suggestion and start eliminating sensors, if its none of these, guess its the vvti itself and sadly the most costly, it may just be gummed up as by all accounts this can happen and restrict the movement.
Problem is i cant even get any live data as its just too old to test.