4A-GE MK1 Engine Rough idle

4A-GE MK1 Engine, revving, problem, idle, back, kicks, drop, revs, stalls, solve, ideas, supply, fuel, suggested, problems, difficult, idling, idles, counter, guys, messed, basically, 4000, start, rough

Hi guys, I have a few problems with my mr2 mk1 basically when it is idling it only idles at about 500 rpm and it is very difficult to get iv revving from that and when it does start revving it does not really rev above about 4000 rpm (unless the rev counter is messed up) and when I let it die down the revs drop very low and it almost stalls before it then kicks back into its low idle. It has been suggested to me that it could be a fuel supply problem does anybody else have any ideas on how to