idle issue after 60+ miles of driving

[05gmcsierra]

got a question.. i tuned my buddies truck.. everything looks good but after driving the truck a full day or an approximation of 60 miles the truck will slowly start surging when slowing down.. after it does it the first time the surging just gets worse until he cant even keep the truck on because it surges to a straight shut off.. any ideas? i flash fresh tune and he will drive all day no problems till the end of the day when it will start doing it again.

i feel like i disabled idle learning but it will still do it..

truck is lq9 230/238 cam 600/600 114 on a 3600 stall long tube headers 4.10 gears tbss manifold with 90mmtb suggestions? ideas?

[joecar]

Post logs of when it happens.

[05gmcsierra]

Post logs of when it happens.

look at frames 440 and 700 i notice it starts to surge and timing wont move around too make it better... so i did make one change yesterday and had my TC come off at 20mph vs 3 and that seemed too fix it but we wont know until today when he drives around all day so ill find out later today if that worked.