When I drive and stop at a robot/ stop and there after pull off my cars RPMs rise but my car doesn't accelerate until I pump my pedal a few times then it'll accelerate it doesn't do it when I switch my car off and start again it only does it after a while of driving. When my car idles the RPMs are very low at about 600 RMPs as well and it has rough idling and the RPMs jump. At a high speed the car is fine. We have done a diagnostic but no faults are picked up, but we don't know if the previous owner cleared all error codes.