RON 98 Petrol

[Gambit]

your timing is out

the 16v ECU can only advance/retard so much

[Gambit]

id stick to one type of fuel and set the timing from that - then your sorted

i found running my car on LRP, BP Ultimate & Shell SUL caused all sorts of timing probs even though they are all 97RON

so now i just use LRP as its the cheapest, set the timing and left it at that - hasnt skipped a beat since

[vwsystems]

i dont know if i ve said this but

the octane rating in petrol if not used quickly..... ie optimax not many people use it, the rating drops if its stored too long...... how long this is i dont know.....
but thats probibly the case........

old optimax will have less octane then the fresh daily delivered supermarket petrol!

i could be wrong but if timmings bang on then i guess this is the case as if there was something wrong with your hall sender or ignition module then it would show up on the supermarket petrol...........