I had a similar issue with my '07 FXT. I was running COBB 91ACN Stage 2 map (AP v2, COBB downpipe, stock intermediate pipe, 2.5" Prodrive axleback), and would spike the "Live Data" boost gauge to 18.4 easily. I think 18.4 is as high as it goes. Same continued after swapping in the VF43, STi TMIC and STi exhaust headers, running on the 91ACN VF43 map.

I had the car tuned last week, target was set to 14psi tapering off to 11psi. "Live Data" gauge no longer spikes to 18. Also, tuner said his mechanical gauge was showing about 2psi lower than the AP.

So, in my case looks like the AP was reading about 2psi too high, and the OTS maps weren't as conservative as my current tune.

Stan

 

Repost, interweb glitched.

Stan

 

I have a 07 sti and when I bought my ap it was shipped wrong and I did the same thing it also speced out high levels when i got the correct unit it went to normal i was hitting 13.7 psi stock no mods.