Interesting Throttle Response

[andyhaug]

I have a 2015 5.3 with a 6 speed. Over the last month as it has started getting cold out I have noticed an odd behavior after my truck sits while I am at work. If I start it with the key, wait until the gauges are done homing, put it in reverse, then touch the gas pedal it will lurch backward out of the parking spot. It seems like this is only if I start it with the key and go to reverse as soon as the gauges are done homing. If I wait another 30 seconds it will not do it, likewise, if I take the truck to lunch it will not do it. It seems like it needs to sit long enough to completely cool down. It seems like it is adding the high idle with the accelerator position, but what is weird is if it sits 30 seconds more it is still on high idle but does not have the same response. Anyone notice this behavior? I can already hear the dealer telling me this is "normal".

[hirdlej]

I never shift mine out of park until the RPM's are down around 700rpm's or so. I always thought this was bad for the transmission. Sometimes on a cold morning I have to wait a full minute before the rpm's get to a point where I'm satisfied.

[sk]

Don't you put your foot on the brakes when you shift it out of Park???

[andyhaug]

I do. It doesn't lurch until I touch the gas pedal. It sits still even on the higher idle. As soon as I go from brake to gas with even the slightest pressure, it will lurch backward.

[MikeNH]

Sounds like it's the engine still on high idle during warm up. Newer vehicles run at high RPM when cold to get the cats to light off (reach operating temp). My Jeep does something similar. It'll run above 1000 RPM for a bit, and it gets longer when cold. I try to avoid shifting from park till it's below 1000.