4.0 hesitates leaving idle.

[tonyjklh1]

ok when i give it some gas it likes to have a delay(also seems its slows down during the delay)then it will pick back up. the faster i give it gas the more noticable it is. the engine idles kind of rough also. and the gas mileage is at 12!! i am guessing the problems are all related. i have changed plugs, wires, oil, air filter, temp sensor, tps, and idle air valve, and both oxygen sensors. does anyone have an idea what might be causing it?

 

[turbotaguy]

My 04 does the same thing, with an emphasis on rough idle. I am new to this forum (and just recently bought this truck) and I have scoured looking for information on rough idle. I have also done wires/plugs/02 sensors, etc and nothing has helped.

For as common as this problem is I am surprised that the "collective mind" of the forum hasn't posted a quick, common solution. I did see someone post that after replacing tons of stuff his rough idle turned out to be a harmonic balancer.

How do you diagnose the balancer? Does it crack or something?

 

[Rangersrule91]

i dont wanna sound like a smart*** but did ya change out the fuel filter, once those things get clogged up its bad news.

 

[tonyjklh1]

Yes I have changed the filter about 1200 miles before this problem