Hey guys some help please!

Alright guys I have had a fuel clatter problem for about three months now..and it is starting to drive me NUTS....If you are willing to read then here goes the story...When the fuel clatter started I did the easy step and changed the fuel filter, and then ran an injector clean through a tank of gas...after that I took the truck to both local chevy dealerships and had a fuel burn test and the injectors tested and they said that the injectors were fine, I have changed the plugs, the air filter and ran the magical seafoam through the engine as well....I am still searching for what I think might be a vaccum leak...Do you guys have any ideas of what to check..the truck runs fine otherwise...Thank yall very much....DC

What do you mean by fuel clatter?

I guess it would also be called dieseling..I don't know if I spelled that right...does that make any more sense?

does it do it from the time you start the truck and is it constantly doing it ?

No it does it when I am acelerateing if I am on the interstate with the cruise set it does not do it...and I do not have to be heavy in the gas when I am accelerating for it to do it either..does that help?

the more gas you give it does the clattering get loader? reason i ask was wondering if you may be mistaken this for clatter from the heads maybe being bad gas or something or low octane

Did the dealership not recognize the noise? A chatter from the motor that gets louder and fast with engine RPMs can be a bunch of different things...too low of octane rating, a broken or damaged valve spring, a bad rocker, a damaged lifter, piston slap, a starving oil pump, etc. I would try and run a tank full of 93 octane to see if that solves your problem.

Did the dealership run a fuel line pressure test?

The dealership did not run a fuel line pressure test but...would a faulty plug wire cause the clatter as well? I kinda want to keep to the simple things first before I tear into anything for no reason. I will try running 93 through one time as well..

if if clatters at idle and it sounds like its coming from one of the valve covers just put your hand offer it and see if you can feel it ... txar mentioned some good ideas of what problems it could be

Thank you guys alot, I will let you guys know what I find