my car boosts fine in 1st gear but when shifting to 2nd it will boost to 3 or so psi. same in 3rd gear. sometimes it boost the proper boost but then slowly to 3 psi and stays there. car moves but there is no power. when i'm in 5th and go full wot, there are no boost issues. this problem happens 70% of the time. i tried the search engine and the archives but reading them, i can't find something that is similar. thanks in advance for any advice.

 

It could be a list of things, I would suggest doing a full silicone vacuum job, and while doing that, pressure test every solenoid, make sure none of them leak. There's a thread about how to test for it on the board somewhere.

I had this problem, and after 5 solenoids failed the pressure/vacuum test, I replaced them, car ran great after wards.

 

check valves