93 s13 ka24de idle problem.

[Audio Puppet]

OK so i done my research and my reading but i ran out of things to try. so my problem is that when I'm driving and put the car in neutral and the car is costing, my rpm's drop to 500 at times lower and once i come to a complete stop the rpm's jump to 800. when i do track events and i run the car kind of hard and i do the same thing, costing in neutral the car just stalls over and over. NOW i did my reading and i did what people recommended. i took of the IACV and cleaned it with brake cleaner. I also cleaned the MAF with MAF cleaner and i checked for any leak's and nothing, problem continues. i also changed the fuel filter and I'm still having this problem. next thing I'm going to do is what i read is to re-locate the MAF ground. has anyone ever heard of the re-locating the MAF ground? and what other things can i do to fix this idle problem?