Piper turbo arrow manifold pressure inconsistent

[lev8rdoc]

Hello everyone. First post to the forum so hopefully I am posting it in the right location. I am hoping to get some advice on potential reasons for a recent development with my 77 turbo arrow III regarding a change in the manifold pressure readings during takeoff. Until just recently, I have been able to get 41” of pressure around 2/3 throttle during my takeoff roll, but now my plane is struggling to hit 41” at full throttle and sits quite steady at 38” 2/3 Throttle. The only change in my routine is that I am currently at about 5000’ altitude with some higher temps but even with that, the turbo is supposed to produce 41” up to 12000, and I haven’t been above 8000 density altitude while testing. The pressure readings are erratic as well when high throttle. At full throttle I can get to 41”, (which I have never had to do before) it will hold for about 5 seconds then overboosts, causing me to retard the throttle almost 1- 1.5 “ to hold 41. I have gone through absolutely every connection on the intake, checked my fittings for the manifold pressure system and looked for major issues with the exhaust side as well but have found absolutely nothing wrong. Could this be an issue with the fuel system not providing enough pressure? At full throttle I show about 22-23 gph peak, but never paid much attention to the rate prior to this issue. I also have the JPI EDM-830 that I use more than the original steam gauges in the Lower panel. Any advice or experience with this will be greatly appreciated!

 

[sgavette]

 

[lev8rdoc]

 

[sgavette]

 

[lev8rdoc]

 

[sgavette]

 

[Azpilot]

 

[lev8rdoc]

 

[Azpilot]

 

[lev8rdoc]