my friend has an ls/vec with gsr head cams pistions.. everything gsr, but on the car idle's from 1,000 to 2,500 rpms like up and down.. i looked there was no vaccum's that fell off so any idea's on what's the deal?

 

Could be number of things, TPS, EACV, FITV. I would do basic carburator cleaning on the EACV and FITV make sure the plastic screw inside is tight all the way. FOr the TPS locate the middle wire on the clip and test the voltage with a multimeter. Should be .45 Volts. You can also put your finger on the bottom hole inside the TB and see if that calms the idle. Let us know whats up.

EACV is located on the back on the manifold and the FITV is attached underneath the TB.

 

it is called IACV
Idle
Air
Control
Valve

 

when i was doing mines, and many others, a lot problems came from IACV. seems to be most of the problems that i encounter in swaps. not just lsvtec but just ordinary swaps.