I'm not familiar with P1516, but
a google of "ford P1516" found this at JustAnswer:
ok you have the cable actuated set up, follow the cable to the solenoid, and unhook the cable, see if when you unhook it the cable is able to move the piece on the intake manifold easily, the solenoid is the faulty component, but just make sure it did not burn itself out trying to move a stuck runner in the intake. Replace the solenoid for the pass. side bank of cylinders, that is the #1 bank, and the problem will be fixed.
Read more: What is the fix for a P1516 (Intake manifold run... - JustAnswer
Incidentally, I have a Civic Hybrid that "shuddered" on acceleration from dead stop.
Honda has a specific tranny fluid requirement that is not matched by "compatible" ATF.
I had to refill the tranny with the genuine stuff. A second refill was required about 3000 miles later to further "clean out" the unknown AFT. That eliminated the shudder behavior in my case.