Hi All

Thanks for replies, very much appreciated.

No EGR on This, Fuel trims alway stay within 5 % Lambda sensor always between 0.485 & 0.515 on steady throttle, (wide band ) Not seen it stray even when fault occurs ( only had very mild symptoms when monitoring.

Interestingly, went for a run with Texa EOBD data log attached and it recored a fault P1603, throttle body fault. Fault code was not logged when problem occurring, but on Overrun. Why that has only now appeared I am not sure

I have arranged for a throttle body to be fitted next Wednesday (local dealer not very helpful) so will report back later.

Thanks Aidan