99 tahoe backfire

[Victorthadon]

Hey can anyone help me with a 99 tahoe backfire I'm going to post a video but first let me explain. I have changed fuel pump, upper intake manifold gaskets, lower intake manifold gaskets, distributor, ignition coil,tps,iac,maf,iat,sparkplugs,wires,crankshaft position sensor,did a new oil change every single fluid is replaced idk I'm breaking my head for 8 months ima bout to jus throw out the whole truck :/

 

[Schurkey]

WHAT ENGINE?

Have you tested those components before replacing them? Did the new replacements change anything?

WHEN does it backfire? Acceleration? Coasting? Engine cold? Engine hot? Low speed? High speed? A few times a month, or every six seconds as long as the engine is running?

What is the fuel pressure?

What is the cam/crank sensor alignment?

Does the electronic spark advance work?

Any chance you've got a wiped cam lobe and one or more exhaust valves doesn't open?

Any chance you've got a non-sealing intake valve that allows combustion pressure back into the intake manifold?

 

[weaponoffreedom]

Fuel pressure regulator, and the vacuum that goes to it.