Hi everyone. im new here and new to Jaguars, i bought my 99 s-type today! on viewing the car the engine was fine, really smooth, it is definitely not misfiring. i have read a few post on the internet about idle problems but i thought id ask here... when sat in park or at a junction with my foot on the break (for an extended period) the car will slowly start to idle oddly (revs drop and increase, drop and increase... it even cut out once). i have had cars do this before and it was the IAC valve. a friend of my fathers said it could be an air leak in the intake (after the air mass sensor). just wondering if anyone else has played around with a problem like this and if they could suggest the cheap fixes to start off with before changing coils and plugs etc.. the car as 100k miles and full service history thanks Mark :)