Sounds like you simply do not have a good tight seal on the large hose that runs from AMM to Throttle body. It is also possible That there is a crack in that bellowed critter and you can't see it.

My only other thought would be that the Brake cleaner is a bit to strong to have been sprayed into The AMM. I use it for lots of things but when it comes to plastics and electronics, I don't use it.
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'75 Jeep CJ5 345Hp ChevyPwr and two motorcycles: it wasn't Volvos safety , it was Longevity that sold me

Could be a bad fuel pressure regulator. The best way to check is with a fuel pressure gauge installed on the fuel rail (35 to 40 psi) This is never easy to acheive due to the type of thread present on fuel rail.
Another method is- Remove vacumn hose on FPR and see if any fuel leaks out. If so replace FPR. If no fuel is present on vacumn side remove fuel return hose from back of FPR. Get a 6' long piece of fuel hose that will fit on the return connection on FPR. Drape hose over fender and into a container (1 gallon minimum). Have assistant start car and observe how much fuel comes out of your temporary return hose. If its less than a full hose amount you probably need to replace the FPR. Mine was just a trickle. You don't hear of many injector failures here on the BB.
Needless to say, be careful about fire, have all pilot lights, etc.(in garage) turned off

check and clean the throtle body and check the connection for the tps.

Also make sure the connections on the injectors are tight.

Check the amm connection.

Check the O2 sensor.

Reset the codes