dirver

hey i'm just new, have to say execllent site. A mate told me ti go here for a problem tha i have. I just recentlly installed forged Arias pistons into R32 GTR, rebuilt whole engine and now that motor idles at 1100 rpm when it's hot. I checkd pretty much everything from air filter to even changing tthe throttle body, so do guys have any ideas on what it could be? thanks heaps :headspin: