im sorry for this being soo long for what i hope is a simple problem with a simple solution, but i feel it will help to know the details that i know!
i have a mate who has a 4dr r32...it has only just been purchased a few weeks ago so we dont know the recent history. what i do know is that it was an auto and is now manual and apart from that it apears to be "stock". since the purchase it has had a 3" exhaust fitted, BOV, and air filter put on. when putting the air filter on we noticed the intake pipe to the turbo was loose(because we knocked it off!) after fastening it back on, it went for a drive...the next day when started, it surged on idle reving 2000rpm down to 1000rpm (roughly i didnt check exactly) and it will do that till you go for a drive then it will just idle high...around 2000rpm. although it never did idle lower than 1000rpm before hand - maybe this is an auto to manual conversion problem with the ecu? maybe the ecu needs to be "fixed" to suit a manual gear box?
i first thought to reset the ecu...i used to do this on my old r33 by disconecting the battery, hold my foot on the brake for 10 seconds then conecting it again. so we did that...nothing happened and it still runs the same...is this how u reset an ecu on a r32?
im thinking it has to be intake related as that is all we "tampered" with, or ecu...maybe a sensor problem...i havnt done a diagnostic test yet - 2 reasons...1. i havnt looked that up yet on how to do it, from what i remember reading is its a lot more complicated than the r33, and 2. i have no idea where the ecu is...but i havnt looked for that either!
anyway, enough of my dribble...if you can help, or have an idea on what might be causing it to surge, please comment...(and dont tell me the AFM is stuffed!)