At a higher speed say 50km/h and up my girlfriend's cav which is a 99 2200, 4 speed revs when coasting, The rpm's will drop to 750rpm which is normal for the car, but it then starts to rev between 500 and 750rpm.. any ideas?? The car also idles a bit rough after a few minutes..
Thanks
For starters, try blasting the throttle body and idle air control valve inside with cleaner. Being a '99, probably got a lotta carbon buildup if never been looked at.
