[CDN_Stalker]

I'd say start by getting rid of that 140% spring, PDI springs in past years have been junk (I've checked out a half dozen of the PDI 150%, they range in length between 6 3/8" long to 7", and a lot of the bad ones are made of a thicker wire than the "good" ones), a 150% spring could net you anywhere from 340-450fps. Get a Modify 100 spring from Jugglez, will be easier on your mechbox and more consistant too.

Sounds ike an airleak issue overall, check out everything that seals from the cylinder/pistonhead O-ring, make sure the O-ring inflates properly, then check cylinder head and nozzle mating, then hop up rubber and alignment.

This is also a case of over-upgrading biting your ass. KISS is always best when it comes to upgrading an AEG, but then it all depends on the brand. And not all upgrade parts are created equal, there is some real crap out there that is sold, and that includes big name brands. Best I've found across the brands is Modify, never had any issue with anything by them, yet have seen and found many issues with some Systema, Guarder, Prometheus parts.