Outer Limits 4x4 Board

Hey there all after a day of 4wdin at the river on the way back stoping at the lights through town i noticed when i rev it up and let the rev's drop back to idle it goes way past normal idle speed to about 500rpm it is worse when cold droping to nearly 400rpm and struggles to bring its self back up to normal idle brings self back up fine when at running temp. Also used to start on half a turn now it takes a few turns.
Any ideas anyone ?

Fuel leak somewhere. I had this once after I high pressure washed the engine bay. Had a pin hole in the filter where the water trap is. Got to a set of lights and would nearly die unless ya reved it up.

hmm yeah i dont need to rev it to keep it idling just drops after u give it a rev and let it settle back to idle then comes back up and holds idle but when it drops it almost stalls cause goes so slow but yeah does sound like a fuel leak makes sense since i have lost a tiny tiny amount of power along with it hmm im gonna have to check everything over cheers for your input m8

could it be air in the fuel system, or a vacum leak?

i'd susp fuel line or filter a bit blocked, possibly from crap disturbed when out bashing about.
good to get some compessed air, blow out lines, swap new filter, then use return line to pressurise tank to make easy to prime.
good tip is to fill new filter with clean diesel as well as all the fuel lines trim approx 10mm off the end so when they slide on the fittings they locate on a new spot to prevent leaks.

hmm seems to of fixed it self lol idling fine now when rev up and let it drop hmm wounder if i should run some cleaner through and change filters?