tackle_TAART

Hello gents, before i post on the forum i thought id quickly ask on here for abit of help, i have a 53 plate WRX STI impreza, and im having some problem with overboosting, i have boost guages and a ECU moniter installed in my car but unfortunatly i havnt got car knowledge installed in my head, a friend of mine said its possibly a dump valve not dumping, but the turbo and dump valve are standard as far as im aware. I noticed this problem last night but in the last week iv noticed when my car is idle it has been sitting at 1500rpm when usually it is under the 1000rpm and also it might be a coincidence but a guage that wasnt working before which is oil pressure has started working. Any ideas boys or any1 know somewhere decent in Chelmsford i can take it? Thanks in advance. Matt