On my profec boost controller my vacuum at idle is staying between -33 to -35 and I've read that it should be -18 to -20. I believe this is causing my bad idle problems and when I let off the gas and push in the clutch while driving the rpms drop drastically and it tries to stall. What could be causing this? If it was a vacuum leak wouldn't there be less vacuum?

 

What are you using as your vacuum sources? Also, your BOV, are you recirculating or venting? Sounds like a leak to me tho, but I need more details please.

 

Vacuum sources are coming from my throttle body.

Vacuum hose after throttle plate = GReddy Profec B specII boost controller, Autometer Boost Gauge and GReddy Type-S BOV (Recirculated)

Vacuum hose before throttle plate = lower nipple on BOV

Would this also cause my CEL to come on?

 

Unknown on the vacuum hoses on the 4G94 TB, but on my 4G93, one of my TB nipples (the one for the cruise control) was not producing any vacuum at idle. As a result, I was not getting accurate readings to my boost gauge. Might be the case here too. Change your vacuum sources and see if the problem persists. you SES light will come on if the car is constantly dropping the idle to below norms and the ECU has to "pick" it back up. You can always double check with Autozone to make sure this is the only code being thrown tho.

I suspect your vacuum source isnt pulling vacuum at idle. Check that and let me know, bro.

 

Thanks for the help

I'll let ya know what happens.