I had some similar problems after I bounced my car to a stage 4. When the ABS & PSM failed, that was my MAF toasted. When she wasn't sustaining boost pressure, I had a boost leak in one of the hoses and there was also some "boost pressure valve" (i know its not called that, but can't remember the name) that went bad. I ended up replacing all the boost hoses with EVO hoses, replaced the valve and upgraded the wastegate springs. Now i see spikes of 1.3 and can hold 1.2 (what to expect with K24) If you don't have new spark plugs, replace them as well.