E78 throttle fluctuation with constant pedal position at constant speed

I'm totally stumped with this stupid issue.

e78 running a L96 motor from 2013 2500HD 4wd 6.0L gas
t42 running a 4L60E from 2013 1500 2wd 4.8L gas, has a mild shift kit and corvette servo installed
no other modules installed, its in a pristine 1981 cadillac coupe deville
TB, pedal, and intake manifold are from a 2013 6.0L Caprice. all diagnostics for both parts pass at all times.

yes, the two modules and engine/tranny combo work fine together, though it did require a lot of custom wiring, including splicing the speed sensor wires together so the one sensor can feed both modules.

the issue I cant seem to resolve is whenever the throttle pedal is between 1%-30%, the throttlebody constantly fluctuates between 10%-20% causing a surging. it does not seem to do it in 1st, 2nd, or 3rd gear, but it does do it in park/neutral and in 4th gear at pretty much any speed. it's most pronounced below 10% throttle pedal position. And it only does it while cruising at constant speed or at very light accel or decel.

I have played with practically every torque table, tcc table, and spark table, and I simply cant get it to go away. after making some major changes to the torque tables, I was able to smooth it out a lot in those higher pedal ranges (15%-30%), but it made it worse in the 1%-8% pedal position range.

any ideas?

edited the original post to correct some previously incorrect info: TB, pedal, and intake manifold are from a 2013 6.0L Caprice.

I'd really love some input on what could possibly be causing this issue. It's a customer's car, he has tons of money into it and would like it to actually be driveable without surging at light throttle cruising.

well, I determined that the issue is directly related to when there is a high load on the alternator. as stated, it only occurs at low rpms; 1400 and lower. And I just discovered that it only does it when the radiator fans are running. As soon as I shut off the radiator fans, it operates flawlessly. As soon as I turn the radiator fans back on, it immediately starts doing it again.

Can anyone help me find out how to alter anything throttle related when under low rpm electrical load? because even though you can only feel it in 4th gear, the fans will still be running whenever the a/c is on, and possibly whenever the headlights are on as well [with or without the fans on]

Post you tunes up.

Sounds like it's an issue with requested/desired load in the ECM. The E78 is all torque based, so it will control throttle position to meet the requested TQ values that are programmed.

Attachment 20024
Attachment 20025

attached are what I have so far

I figured it out. the maf was too close to the air filter, it was getting crazy turbulence at low rpm and low throttle at higher speeds. K&N cone filter, wrapped some tape around the front of the filter and around the circumference of the base, and the issue completely went away. So I guess I just need to remake the intake somehow where there's more distance between filter and maf.

Gotcha, you really need 6"+ of straight pipe before the MAF to calm the turbulence down so the MAF can get an accurate reading. Glad you got it sorted out!

yeah I've always followed that rule before in the past for that exact reason, but this car just didn't have the room for it, so I gave it a shot against my better judgement. oh well, proved myself right again haha.
So glad I'm almost done with this car finally, it's been a huge nightmare all along. came out great though overall!