Any serious consequences for ignoring this obd code for a while? The truck runs fine.

 

what year is your truck ? and have you done a tune up ? it probably wont hurt for a while to let it slide, but you need to start figuring it out before other stuff happens...lol..one good place to start is with a tune up (plugs , plug wires,air and fuel filters) a good fuel injector cleaner, and clean the MAF (mass air flow sensor)....
P1178 >>>AMFR (air mass flow rate) Correction at maximum positive value
uou can buy "mas air flow cleaner" spray at most auto parts stores

 

I checked the fuel pressure good at 34-37 pounds, new air filter, cleaned the maf with carburetor cleaner. I did notice that the fuel pressure drops to zero when you turn off the key..

 

carb cleaner is not recommended for MAF's. You need to use MAF cleaner. Any auto parts store will have it and it is fairly inexpressive.

Hopefully you didn't ruin the MAF.