2005 Silverado sputtering

[Chap8231]

I have a 2005, 4.3l, 2x4, extended cab Silverado. I’ve been tearing my hair out trying to figure out this issue. It seems that after the truck has warmed up for the most part it will sputter like it wants to stall out when accelerating after sitting idle at a stoplight until I get to about 40mph or so then it just seems to regain all power and smoothness to driving again like nothing was wrong. Any ideas?

[sefiroxx]

What have you tried?
- checked plugs?
- clean throttle
- clean MAF
- checked sensors via a scanner?

[Chap8231]

I’ve tried fuel and injector cleaners, no change. I’ve tried listening for vacuum leaks and I haven’t heard anything obvious but I’ve got flowmaster exhaust running which makes it slightly louder and harder to hear things like that. Changed plugs and wires, no change. Pulled MAF and it was clean but I didn’t do any cleaning either. Looked at the throttle body and it was slightly dirty on the inside but I didn’t clean it either, a thunderstorm was rolling in...  I tried pulling my gas cap also, I had one go bad on a old truck a really long time ago and just remembered it causing some sort of issue but that didn’t change anything either. One thing that may have made a change but I am not sure on is I left the tube from the air intake to the manifold undone on accident and that seems to have resolved the issue but I am not certain on that all the way yet. 

 

Hopefully that helps. 

[Jstevens7700]

My truck was doing the exact same thing and like you i was pulling my hair out too. A fuel pump was the answer to my problems. If you are having o2 sensor codes on your scanner install them as well. If you want to varify the problem buy a fuel pressure tester from somewhere like harbor freight and see if your pressure ever goes above 30. My truck still pumped fuel and if i was easy on it it was drivable but still had the loss of power with no explanation. Make sure you order the right fuel pump as well according to bed size. This should solve your problem so your hair will be safe lol

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[Jstevens7700]

I did exactly the steps you did as well as install a throttle position sensor. It didn't go away until i installed a fuel pump

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[sefiroxx]

Yes, that will affect the MAF sensor readings as more air is getting in than the MAF reports. Result is a lean fuel condition

[02suburbanZ71]

Use a mechanical gauge to check the fuel pressure at the rail. That is a very common issue and normally the case with these symptoms.