P0455 Code idle issue sometimes pls help!

[Reelgrinder]

every now and then I'll get an erratic Idle surging that 99% of the time will kill the car after it surges about 3 to 4 times. Then you crank it up and it may never do it again for a week or more. Logged tune sent to Bob at HP nothing looked wrong, tuner did pull a code P0455..

I would post in a different area but I haven't been able to account for 3 psi of boost loss. Compression checked by shop all is fine. brand new belt on blower not slipping.

All we know is a Evap Code.. to the best of out knowledge It also causes the fuel trims to act up every now and then and get fat.. The shop also thinks the 3 psi could be escaping through some valve or emission parts..

I kinda need to fix this on my own since shop has diagnosis for free..

So they were trying to tell me to look near the cylinder head and there may also be a line or so that might be pinched..

SO can someone lead me in the direction on where to ck?

I figure a smoke machine might be needed as well but maybe a visual inspection could help?

I just need to know what to look at (pic and example of part) and location.. like how that evap system is setup and does the blower change that?

[Chevy9534]

P0455 is an evap leak. Could be something as simple as a loose gas cap. Many different factors that can cause that. A smoke test would find a leak if one is present but you will need a scanner to seal the evap system. Evap leak will not cause a surge.

[Reelgrinder]

What if it messes with fuel trims might it.. and would it be a possible to lose boost from it. . Everyone says gas cap lol..

[ADM PERFORMANCE]

Evap sensor is directional.....Gray side goes to engine and black side to tank.

It makes a difference

[Reelgrinder]

Ok thank you Andy.. where is this located.

[ADM PERFORMANCE]

Under the hood. Who installed it?