E38 Light part throttle surge/timing retarding causes?

[Age08]

E38 on a ls7 light throttle surge/Timing retards around 45-60km/h in 5th gear rpm 1000-1300rpm, I have tired copying high octane timing tables in the area of surge into the coast down timing table, disable DFCO,& tables for cat light off are all zero'd out and the car still surges under light throttle, you can see during the events that only thing that changes is the timing, the AFR is pretty close with 1-2% when it happens.
Any ideas on what else can cause timing to drop 10-20 degrees during this condition? in the picture below shows a log file where it happens,

[joecar]

You chart shows:
g/cyl dips down
sparkadv dips
after a short delay STFT drops


questions:
are injectors leaking...?
is MAF reading low...?

[Tre-Cool]

had this issue a couple of weeks ago and was driving me crazy..

let me guess, ecu is a manual? see if cfco is turned off.

If it is, turn it back on and see if it goes away, i spent days messing with spark tables and could not get it to go away. i had tried zeroing out idle spark adapts, having spark high/low, idle, coast spark all the same and it still did it.

I think something is messed up when the cfco is turned off. The os i had this problem with was 12639270.

this car i had the problem on was only doing it on the slightest of pedal/throttle usage as soon as the car loaded up it was fine

[Age08]

Thats the exact same thing this is doing, my os 12612281, the only mode to the car is cam 227/243 .649/.660 115 lsa,
The cfco is on,
Ive tried it with/without dfco enable/disable, open/closed loop(worse with close loop), maf disabled,
Tried the same with the coast down timing, idle timing, main timing,
All I can think of is airflow adjustment somewhere must have a timing correction factor coming into play when coasting/part throttle and cam is either above or below that threshold.

[camaro10]

Thats the exact same thing this is doing, my os 12612281, the only mode to the car is cam 227/243 .649/.660 115 lsa,
The cfco is on,
Ive tried it with/without dfco enable/disable, open/closed loop(worse with close loop), maf disabled,
Tried the same with the coast down timing, idle timing, main timing,
All I can think of is airflow adjustment somewhere must have a timing correction factor coming into play when coasting/part throttle and cam is either above or below that threshold.

Lower the closed throttle rate a and b.... Had the same issue and fought for a long time. Multiply stock values by like .3. Matter a fact it was roughly the same rpm and tp% too. For some reason it will pull timing back and forth. I think it is just enough where it jumps from idle to high octane spark.