Running erratic

[Cumminz]

Ive been chasing down this problem for about 2 years and barely drive my truck because of the issue. So I have upgraded to the newest airdog II, new MWFI vp44, and 150 hp injectors, new head gasket, studs, and timbos apps. If you listen to my truck from about 100 feet away, you can hear it running strange but not picked up well on video. It sounds like a random ticking coming from engine like the cylinders aren't firing all the way or something but it is NOT a misfire (more of a random skip). This happens throughout all engine rpms. When im cruising going 55 and let off the gas SLIGHTLY (so little load on engine), the truck starts sputtering and can be noticed on tach (+/- 50-100 rpm). And when coming to a stop (no throttle), it will sputter the same way until i get to a complete stop where you can hear the truck lope (SLIGHTLY) at idle. This truck is not running smooth like it used to. Something happened and nothing I have done that was mentioned has helped it. I have good fuel pressure. Im pretty sure the cylinders aren't firing the SAME but idk. Its very noticeable to me. Any thoughts or tests?

[JAG1]

No tank vacuum issue?

Check for AC noise confusing the computer.

Check for good ground connections everywhere

 

Just a few to check anyhow.

[IBMobile]

So no lose of power or hard starting?  Looks like you've taken care of fuel delivery and air intake should not be a problem. That leaves compression and camshaft timing/profile.  Sounds almost like a gasser with a mild race cam.

[Cumminz]

No tank vacuum. As far as AC noise, i have unplugged the alternator and drove down a few blocks with no change. I have checked the connections for the computers. No loss of power or hard starting. Fires right up but it does sound like a gasser with a mild cam but this truck should purr like it used to not sound like a bad lope. Its not even a cool sounding lope.

Edited July 31, 2016 by Cumminz

[dripley]

The fuel tank needs no vacuum. Sometimes the vent will clog and cause vacuum as the fuel is pulled out causing issues. You dont want vacuum in the tank.

[JAG1]

A bit of air in the fuel lines could cause the problem check the suction side of the lift pump for loose fittings.