No acceleration.. Help please!!!

[Rodeoram93]

I have a 99 dodge ram 1500 4*4 5.9l I bought a couple weeks ago an it accelerates good 1/3 throttle just feels like it has no power behind it but if I floor it the Roma go up to bout 4000 but the acceleration stays the same an still feels like it has no power behind it?? I can't figure out what's cuasing it but when I press down on the throttle it does have a slight hissing sound that it doesn't have at idle. Can anyone help give me some ideas of why it doesn't have any power behind it or why it's not accelerating responsibly to the throttle??

 

[dodge dude94]

Welcome to RF and take a gander at this
http://www.ramforum.com/f61/plenum_gasket_what_where_what_should_i_do_about_*info*-37635/

Might be part of your problem.

 

[Rodeoram93]

Thank I'll check it out an see if it fixes the problem.. I appreciate the addvice