today i put in my 4000 gov spring and in 4 th gear the truck kind of falls on its face does any one have an idea what is wrong

 

Sounds like you got the throttle shaft indexed wrong.

If you are running a 4200 RPM spring it needs to be trimmed to length. What is the 3 digit code on your spring (last 3 digits of the part number)?

 

Also if you plan on running over ~3400RPM, you should put in 60lb valve springs to prevent valve float.

 

i ordered it from pdr the part number is 354

 

if it were the throttle index would it still rev ok in neutral or could it be the fuel filter clogged

 

If it's indexed wrong it will be boggy if it runs at all.

Did you trim it so it's the same length as stock? If not then that is your problem. Pull it back out an redo on of the ends so it's the same overall length as the stocker.

 

it s fixed i tried a fuel filter and that did the trick thancks for all your help