No problem....I would bet a solid 90+% diagnosis then if your tech did my test and the idle stumbled. It's more of a pain in the rear job that takes time....those bastard combi valves need to come off which are always fun (mine are gone now, woohoo!).

Does your mechanic feel confident with doing this? Everyone needs to be a first timer at some point, but I'd be careful as the first time will definitely be more time on the job (aka labor cost!). Mine took about 12 hours over a couple of days taking my time...next time around, probably 8 hours or so since I know it better now.

Not much as far as parts cost on this, mainly labor. You'll need the valve (about $60 OEM), intake manifold gaskets, injector o-rings and little plastic retainer rings (suggested), combi valve gaskets (suggested), and then coolant, etc. depending on if you need to pull a hose to get to service position. Really the only reason to go to service position (if I remember correctly), is to get the frick'n bolts out of the front of the intake pipe into the throttle body since there is zero room otherwise. Fortunately the valve covers can stay on which saves some time and hassle.

Not sure where you are located, but I'd be happy to help if you were anywhere near me in MD. Hope this helps! Feel free to PM for email or phone if you'd like to talk about it...~ Eric