96 chevy running horrible

[Mland.514]

Ok, im stumped... I have a 96 chevy 1500 with 5.7 L gm crate motor that was put in in 2007, it has roughly 20,000 miles on it. ...

Latly the truck has been running like crap, it wont rev up when you put it to the floor, whether your driving it, or in park, it will spit and sputter and try to,stall out. It only revs up in park when you ease into the throttle slowly.... If you ease into the throttle while driving, it will sputter and try to stall it will barly do 50 mph, when it trys to stall when im driving, ill throw it in neutral and shut it off and restart it, it will get me goin a little faster until it starts sputtering again

My check engine light is on, I have scanned it and came up with 3 codes, all O2 sensor codes, p0151: O2 circit low voltage bank 2 sensor 1, p0131 O2 circit low voltage bank 1 sensor 1, and p0161 O2 heater circut bank 2 sensor 2.

What I have done: cleaned every connection for all sensors and inside distributer, checked compression:good. Plugs are good, wires look good. I changed the 2 O2 sensors that are right after the exhast manifold(seemed to help for about 50 miles). Replaced ignition control module, new mass air flow sensor, cleaned throttle body and air filter(i have k&n cold air intake)

Today I checked my fuel pressure and I am getting about 51 psi, and as soon as I shut the truck off, it goes strait to zero psi. A few months ago I put in a new fuel pump, fuel filter, and sending unit.


Im totally stumped. Not sure if its an ignition or fuel problem, or if my cats are clogged, I dont know where to start.

Tryed to be as detailed as I could
any help is greatly appreciated!! Thanks!

[grider]

if you have the origonal popit style injectors they fail and leak this can cause the fuel pressure to drop when the pump shuts off if ths is the case gm has superseeded the design with real injectors you can get them at any parts house i have had a lot of luck with the upgrade hope it helps

[brcidd]

FP dropping to zippo is rotten! You have a leak-- probably under plenum, or inside fuel tank-