Engine jerky before warnup

[Dennis Johnston]

Thought I'd post this up for some other opinions as this started happening about a month ago:

From a cold start, the engine feels like it's lost power when engaging the turbo past half spool, it feels mildly jerky -- like the power wants to come, but doesn't. If I put the turbo to full spool, the turbo sounds fine, blowoff sounds fine, can hear the intake sucking air. There are no discernable sounds which would make me think timing, bad lifter, or a problem with the oil pump. Eventually after about 5-10min, the engine is fine.

My guess is a boost leak with cold vaccum hoses. Thoughts?

[Scott Girvin]

Could be caused by many things. I'd suggest your best bet to find the problem is to do a boost leak test and then log the car.

On top of that....Im guessing FIAV leak.