I have a 2005 Chevy Silverado 4.3l v6 manual transmission truck two wheel drive pretty standard truck anyway when I try to accelerate it spits and sputters going up hill he almost dies out seems like all the power is being gone I can coast around town under 50 km it idles great but dead when accelerating????? I cleaned the intake best I could and there's new plugs and distributor cap clean air filter that's about it I'm stuck any help be great

 

Start by testing fuel pressure per sticky at top of 2nd gen forum. On a 2005 should be 58 psi (not 60) with key on engine off. The rest of the pressures and info in the sticky are correct.

 

If your fuel pressure checks out ok, and your symptom is bogging down going up a hill at WOT, I would suspect a clogged exhaust. Possibly clogged cat. Or cat guts broke up and clogged the exhaust after it. A sympton of this would be rattling coming from under your truck when your driving. You could do a back pressure test by using a vacuum gauge (that also shows psi) and rigging up a fixture to put in place of your upstream O2 sensor. At idle pressure shouldn't be much above 1 psi. Snap the throttle a couple of times and check to ensure that the psi doesn't jump up significantly.