1993 gmc k1500 suburban 4x4

[93gmcsuburban]

truck has less then 200 k the truck never really had any major issues in the 2 years I 
have owned it. since it was older truck i replaced some what i thought was needed 
parts. long list lol "spark plugs, wires,cap and rotor, oil, fuel filter, fuel pump,MAP 
sensor,egr valve,TPS,ignition coil and i believe the temp sensor son changed.verified 
all vacuum lines to the engine and the 2 barrel throttle body". i have cleaned the 
throttle body best i can with out taking it completely apart. my son took the cat off the 
truck and has a cherry bomb muffler only on it.i have not done a transmission filter kit 
yet because i don't know when the last time it was done and have seen horror stories 
about doing one that has never been done or a long time between. my big question is 
when the truck is in neutral or park it revs up nice and sounds very good to my ears. 
when i place it into drive and punch the go pedal it falls flat on its big arse , i can get 
up to highway speeds but i have to go slowly to get there.what else could cause this 
truck to do that ? thank you for all the help i can get on this big beast. i will try just 
about anything before i send it to the junkyard.

 

also over weekend i got a new timing light and verified that it was set at 0 degrees with the advance unplugged and when advance was plugged in i showed 20 Degrees.

[Mikebtte]

Fuel pump. Check pressure to verify but I would think this or a failed open fuel pressure regulator.

[93gmcsuburban]

it is always the simple stuff we over look lol. i changed the fuel filter and her pep is back lol. feel like a dumb arse, i will be changing the injectors next and prob the regulator as well after seeing this in filter

[93gmcsuburban]

thank you again for the info to check