03 Sierra
4.8/5-spd

Cold Air Intake
'01 Spec Z06 Cam 204/211 .525/.525 116LSA
GM Performance Touring Exhaust

I've tuned the truck using HP Tuners and a WB. PE comes in dead on at 12.5, Zero Knock and after about 6 months of not touching anything...

LTFTs are showing 0-1%

The only item I can't track down and truthfully haven't spent much time messing with it...

The truck has an annoying tendency to hold RPM between gears in normal driving. I typically even see the RPM rise a bit with boot off the throttle and the clutch in. It take a few seconds to settle down and can be annoying.

Anyone seen similar?

I am going to set up a PID and do some logs to see if commanded throttle differs from actual - or timing is being added. I did the Russ K idle config today just to double check RAF.

Thanks for any help.

 

Throttle cracker airflow more than likely. You probably had to increase base desired airflow for the cam, that on top of the overly aggressive stock throttle cracker is probably the culprit of your problem.

 

I did this based on a recommendation on idle tuning initially, but it was causing the RPM to hang absurdly. I returned the Base Idle Airflow back to stock.

The enable/disable is set on Throttle Cracker for 2 mph/3mph.

What about the Throttle Follower Airflow Decay ?

 

I would try decreasing the airflow values in the throttle cracker airflow table first rather than mess with throttle follower, and or speed enable/disable. Try cutting the cracker air table in half and see if that helps.

 

So if I correctly modify the throttle cracker/follower that will allow the engine to have better "throttle response"? Seems like these newer engines are lazy compared to the old stuff.

 

Throttle cracker and follower have to do with decending airflow. Optimizing those tables will allow for a bit quicker drop in rpm to idle when revved. Timing and proper ve and maf tuning will aid in increase throttle response when "blipping" throttle. Delete tip in torque management helps too. Torque converter lockup makes the response feel lazy too, you can tweak the enable speeds and tps to delay lockup some at part throttle. You could also set your power enrichment enable tps% lower for a quicker entry, that makes part throttle feel much better, but mileage will drop some due to the increased fuel consumption.

 

my truck does this stock, and its very annoying lol