2007 Sierra 4.3 stalling losing power

[Jimbo193]

Hi everyone I need some Help with my 2007 Sierra 4.3 2wd. It ran great up Until about a month ago it randomly started to sputter and lose power. It would run ok for a few minutes then lose power, bog out when revved up then eventually stall out. Fuel pressure is around 60 with key turned and it holds there no leaks. Also I should mention that when it is first started now it runs great for probably 10 minutes then starts to act up and gets worse until it stalls. If I shut the engine off and let it rest for 10-15 seconds it’ll start up and run great again. Very odd

 

Since then I have replaced a lot 

-Fuel pump (theres no Filter on this truck)

-spider injector assembly.

-spark plugs, wires, distributor, rotor, cap, camshaft sensor

-crankshaft sensor

-oil pressure sensor 

-purge valve the 1 under the hood and the 1 by the gas tank + solenoid vent filter 

-both upstream o2 sensor 

[Jimbo193]

Forgot to add there’s no CEL codes

[Jworks]

I had the same, or similar issue once with my 4.3.  It was the catalytic converter stopped up.  I had to put a new one on.  It was expensive.  There are tests that can be run to check the catalytic converter to verify if its stopped up or not. 

[richard wysong]

I agree with Jworks, try taking the upstream o2 sensors out and running it. it will be loud but that will tell you if its the cat. aftermarket weld in cats aren't that expensive. theres usually a reason cats fail so if thats what it is you need to investigate further so you don't ruin the new 1

[richard wysong]

you may have already replaced what would have damaged the cat tho

[dna9656]

Sounds like debris in the fuel line.