SS101

iTrader: (2)

i thought it was just your run of the mill overported tb but after i backed out the idle adjustment screw a few turns the rpms dropped back to normal for a little while (500 idling in gear vs 700). its not much but its enough to throw codes for high idle and lean on both banks.

here's the unusual part, after it was normal for a whlie it crept back up to around 700 and the screw didnt move. now sometimes when i pull up to a light it will drop to 500 and then slowly creep up to 700.

if it was just an overport would it drop all the way down to 500 and then slowly creep up or would it just drop right to 700???

this is the second ported tb to do the exact same thing btw.

jimmyblue

iTrader: (11)

TB porting of any sort will not cause a lean code.
High idle and lean points to a vacuum leak. Which
may be why the second TB is no different than
the first.

SS101

iTrader: (2)

curiouser and curiouser...you bring up a good point. any idea where that leak might be? the only thing i've touched that could have a vaccum leak is the TB itself...where else could a leak that small be coming from??

jimmyblue

iTrader: (11)

PCV hose can crack or scuff open. Vac lines
may come loose at the back. Intake bolts may
want snugged. Injector O-rings can get mis-
seated if you played with those.

If you are going to use old-school leak detect
methods (spray propane or carb cleaner) you
should unhook the IAC once motor is warmed
up, so IAC can't fight the drop/rise in RPM you
are listening for.