going crazy

[v8vlwags]

hi all,over the last week at idle car every now and again drops revs 750 down to 400 bounces back up then today it was in park and revs were jumping constantly from 750 to 1200 like somebody was reving car ,oh yeah its a vx v6 n/a any ideas? thanks

[airforceone]

altinator , regulator. good place to start lookin

[dannyn12]

iac valve on the throttle body could be the problem

[delcowizzid]

check error codes

[v8vlwags]

checked codes 0012 was all that eas there which i think means operational,no vac leaks i could find any other ideas,im stumped

[Tree cutter]

I think dannyn12 is on the right track.

[v8vlwags]

changed iac valve got no where with that,changed battery today nothing there either,seems to miss under load every now and again,i will change plugs tomorrow and fuel filter .changed purge line to 1 of my vs hoping that was it but not that either mmm now im going crazy chasing this

[v8vlwags]

righto,reckon i found the vaccum leak where the plenum chamber meets the intake manifold,sprayed wd 40 there today and revs jumped up a bit so hopefully got it.while im at it im going to clean out chamber,just want to know is it worth doing anything in there i.e polish,port etc any help would be great thanks gavin