my truck sometimes feels like it misfires. it happens in every gear (5 speed) when you accelerate below 1500 rpm. it sometimes does it above 1500 rpm, but rarely. you push the gas down and the truck jerks a couple times as its accelerating. does this sound like a fuel filter?

 

Have you checked fuel pressure, vacuum leaks? Fuel press. should be around 60 psi. You check it on the pass rear of the upper intake manifold. The 4.9 is also good for clogging fuel injectors. I have seen it take two to three flushes to straighten them out. What year truck? Two tanks? If so, does it run better on one than the other?

Robbie

 

its an 89, and it has 2 tanks. im actually having a problem with the rear tank, the switch on the dash doesnt actually change what tank fuel is coming from (it always comes from the front tank), it will just change the gauge over and show me how much gas is in there. what did you mean by flushes? if fuel pressure is ok, should i go for some of that seafoam stuff? and if so, should i put it in the fuel tank or the engine oil? thanks.

 

My engine is doing the same thing bad under 2000 rpm, and above 1/2 throttle its doing the same thing.. i belive mine is a extream case of what yours has.. did you find a solution?

Jason