The bobbing when i come off throttle and truck is trying to idle is getting worse with the increased temperature outside and when i have my ac on when it revs up it blows quite a bit of smoke out. It stops when i get to a speed less than about 10mph. Question is could i break the vss line momentarily or ground it out to trick the ecm that i stopped and return to a normal idle? 

Valve lash. Check this first.

 

As it gets warm or hotter outside the problem get worse to the point it possible to stall.

valve lash is good. problem stops 100% if i go below ~10mph. seems to be computer related. 

It is computer related.  The ecm thinks it needs xxx fuel to idle, but since you have big injectors you only need yyy fuel.  The ecm over fuels then under fuels

i understand that but im looking for a way around it. if i disrupt the vss signal momentarily would that trick the ecu i was stopped and solve the issue?

Logic would say yes, but I'm not me either

Is suppose that would fix it.  The ecm doesn't go into idle routine until mph is near zero, like you noticed.  

 

Is it causing a big enough issue to want to fix?

ya when i have my ac on it causes it to bog down enough it pours out smoke trying to recover and it gets real old as im coasting to a stop im puffing a cloud of smoke out every few seconds or i can kill the ac and its not as exaggerated. im thinking about a momentary disconnect activated by the clutch.

I think you should try dropping your pop pressure down to 330 - 340 bar.

Edited March 22, 20187 yr by kzimmer