Hi guys

My evo iv is running mint starts first time everytime seems tobe running fine until its warm and usually after a fairly long drive will sit idling and randomly it does a big drop in revs but quickly picks up sounds like its almost going to turn off then it quickly picks up it only does it sometimes and when its warm, however usually when cold start up it will rev 1500rpm by itself and slowly work way down till operating temp, lately I start it and it starts to drop to 1000rpm idle straight away?? its boosting fine 15psi as thats what its been tuned for and hasnt been rough or hard to drive? what could this be

It has 255lph ful pump
evo 6 injectors
evo 6 ecu
It was dynotuned a week ago and was getting plenty of fuel and had to take a little timing out of it pretty rare usually need put more timing into it so its fine other then these two very annoying things that seem to be getting a wee bit worse and worse as time goes on.