hey, my car has started to play up on me, i always have the car parked in the garage with the battery disconnected, its probably been sat for a good 3-4 weeks when i decided to take it out for a blast, everything was fine until it wouldnt rev passed 4k then 5 minutes later it rev right through to the redline but then again 5 minutes on it would stop revvin at 4k, can any1 help me on this??!!