870 pedal delay/ throttle response issue

[DCtruckin]

my 870 has this issue where as you are going through the gears when you let off the throttle to shift and go to accelerate again its extremely hard to make the truck shift smooth on the low end. Its as if there is a delay or a dead pedal at the very very top of the pedal. so if I dont take my foot completely off the pedal and shift like I am 16 years old, it will shift smoother than if I am trying to baby the truck like I normally do. 475hp tune demandated via running rough, also with an intake manifold. This little issue has been around longer than the tune. And also the truck seams like a dog, traffic light to traffic light, but once its on the highway it will go and pull hills fairly good. I did put a new throttle pedal in probably 2 years ago. does it need to be calibrated? timing or metering actuator problems? trying to make this thing more pleasant to drive around town as most of my work is local hauling.

[Rawze]

you might have to monitor the 'fuel control state' while its acting up to find out why its holding fuel back. If it is the pedal, then it will say it.. if it is a boost or other silent derate, the it will report that too.

Running rough is the resident CM870 guy .. so if he made the program, he would know how to help you monitor that to see what the issue is.

[DCtruckin]

@rawze the truck also did this before the tune, and also often when you put the clutch in the rpm’s will surge really low then up above idle then back down to idle. Not every time but often

[Benjamin9669]

Mine seems to always have done the same as if there is no smooth smooth shifting.

[3406E]

Lol mine does weird stuff like that, I use my toe on the throttle through the low side lol. And start off in 3rd

[Chamberpains]

I remember years ago i made a post on here of the nightmare I had of a sluggish intermittent acceleration in a 9400i with a cm870. As Rawze posted, monitor the engine state during acceleration. I also had to monitor the TPS sensor voltage for days while driving. Not just the TPS percentage. I had found the position value would read accurately but the voltage would intermittently stagnate, stick or would creep up from base value.
The problem ended up being the 3 TPS wires from the ECM to the bulk head pass thru were braided and wrapped around the back of the engine had wear from being old. It had multiple spots that were worn into each other once I pulled the braids apart. Not worn enough to show green cheese or exposed wires. But close enough to get cross voltages. Fix for this was to cut and solder splice the whole length of wires all the way around the back of the engine. DO NOT BUTT CONNECT ANY SIGNAL OR SENSOR WIRES.