Just noticed this this morning on my Ty. As I have my foot on the gas I noticed the boost guage go from around 4 psi to the 15 mark and imediately back down to low psi without my foot moving the pedal up or down. It would do this every time a little boost was required. It isn't a guage problem where as I could hear the turbo increase and decrease as well as feel the Ty surge and let off. It has just started doing this. I even noticed that when I mash on it (not wot) that it was doing it, psi would spike and back off, jump up again and so on.