Cheers for your help guys - I have tried changing them all to known working platinum plugs (the ones I took out of the car were all perfectly fine and only covered ~5000 miles)
My problem has worsened and is a tad confusing.
If I turn the keys, starter motor cranks but the engine doesn;t fire and just keeps turning forever. BUT if I turn of the ignituion, switch back on she almost catches and everytime I switch off and on (needs about 5 times) it gradually gets closer to starting and eventually fires up - car runs fine on full boost, under load etc but on idle she is missing often (not rhythmic - makes car vibrate when missing).
From searching the forum it could be coil packs, but why would this get easier to start everytime I switch off the ignition? I could be missing something obvious that some of you supra Guru's out there might know/common fault etc.
Please help! I have no idea how to diagnose this! Thanks in advance!