Gen 4 off idle flat spot or better known as lag

[Rick P]

This is what i did to get rid of the dreaded flat spot or lag off idle, I disabled spark smoothing,under desired throttle area i switch from Vss to RPM,under idle spark advance i lowered the first two rows 2 degrees and raised the idle coastdown up 5 degrees in the first two rows. Now weather rite or wrong holy jesus this thing really woke up. My truck is a 2013 siverado 1500 4WD with a 5.3. I'm in no way shape or form a pro i'm like most at still learning but i asked for help and that was a joke, either no one knows or just won't tell, either way i figured it out and for me after much scanning everything looks great. I hope this helps someone with the same issue.

[GHuggins]

It's not "politically correct", but you can also lower your etc scaler by about 10% to help with this too... Just don't do this if it's FI... This gets around the lag built into the throttle tables themselves that we typically can't adjust...

Sounds like you gave it more cushion room for the spark controls and in turn gave it more spark when deceling and stomping the throttle - never thought about handling it that way - not a bad idea as long as it doesn't cause coastdown return to idle issues? Nice job on that one

[Rick P]

I have zero issues I've logged it for 5 days and all is healthy,for me it's not about racing or beating on my truck but the lag was irratating the hell out of me so took it opon myself to figure out a fix,i will admit it's touchy but so isn't my twin turbo lq4 in my67 nova lol.

[kansasjk]

Rick P, pm'ed you.

[J-CUE]

under desired throttle area i switch from Vss to RPM

Rick,
When you changed from VSS to RPM, did you also change the axis with RPM values in the throttle area maps?
From your report, I'm guessing you haven't went into REP mode?

Thanks for sharing your work with us!

[Rick P]

No I didn't change those, for my particular truck the way I have it set up it works perfect once I got use to the touchy throttle responce it has now, im still new at this so I'm still learning and open to suggestions

[MMGT1]

If you stomp it and get timing dropping to 0 in spots, it'll happen with huge intakes, scan and adjust for exceeding the allowed air flow changes in your tune. Just remember not to blindly add to that, scan and give yourself a bit of headroom over your max values.

[will15]

I have used about 100 different timing combos to try and fix this problem with a heap of different results but I have not tried the throttle scaler switch to rpm, I'm gonna give it a crack.

[Rick P]

In the ETC Area scalar i also changed mine where the 25 was to 00 much smoother throttle responce just a much more enjoyable driving truck the other thing i noticed is i also no longer have the bag shift when it downshifts alot better on the drivetrain

[Jggregory99]

Any chance you could post the tune.. Not sure I'm following where the changes were made...I'm a Newb... So I am trying to see all the different angles of tuning and ways of "Out side the box" adjustments.....

[Rick P]

I'll try today,as a notice this isn't done and I also run only93 octane so my high octane tables are up there