having difficultys

i have an 88 K5 blazer with a tbi injected 350 and i cant make it go over like 20 mph or so, i read on a link that it could be a torque converter but isn't that only under load or could it be bad enough to do it when not under load? i replaced the fuel filter (actually still am, wouldn't connect enough leaked gas) any who, i get up to about 20 and the engine burbles and the truck "jumps" and shakes and i dont know what could be the problem

if it ain't the filter most likly its the pump. any black smoke or flooding happening?

Sounds to me like maybe your trans or tourque converter has packed it in .

Yeh definatly something wrong in your trans or torque converter. So unless you've worked on that type of stuff before it would be a good idea to take it to a mechanic.