2000 Silverado 1500, 5.3L 4L60E 4x4
Weirdest combo ever, I've been told something different by everybody.
Bogging after starting engine, significantly worse after cold start. Gets better when warm, but still noticeable and struggles bad with hard acceleration. Terrible fuel economy (9mpg / 24L/100km). Feels 'gutless'. If cold enough I'll hit RPM ceilings and can barely accelerate.
I've replaced fuel pump, fuel filter, fuel regulator, cleaned grounds, checked relay, and run injector cleaners- all of which made no difference. I'm reading very low fuel pressure (45psi idle, barely reaches 50psi when revving)
Unplugged upstream O2 sensors, catalytic converters don't seem to be clogged.
Rough shifts lead me toward MAF sensor, and when I unplugged the sensor the truck felt much better- idle even felt smoother. Running off preset data is rough but much better than live data, the engine doesn't seem restricted beyond the ECU.
Any thoughts? I'm completely lost on this one, its my daily driver so I'd like some better fuel economy haha