$8D occurs around 1400 to 2000rpm. At about 40 to 50kpa. You can really feel it when the TCC is locked cruising down the highway at about 45-55mph. The car bucks and the tach will bounce. Its a miss somewhere. I added fuel to the area, removed fuel, added timming, removed timing, added fuel and removed timing, added fuel added timing, etc. No change at all the bucking is still there....what am I missing?

 

EGR?

 

running a HSR...dont have one....

 

what are you guys with similar setups running for cruise timing?

 

The only thing that comes to mind is low trans pressure not holding the TCC firm enough? Not sure if thats possible. The MAP reading may bounce when the converter slips and the load changes while you are steadily cruising.
The Tach bouncing part is the one that indicates the engine is speeding up and slowing down but very quickly and acting like a miss. Strange place for a miss to happen if air, spark and fuel can't fix it.
Do you have a log of this you can post?

Do you have hiway mode enabled?
The stock 16.1 AFR may be too lean for you in that area.

 

17 to 1 at 2000rpm and you start getting into missing on cruise. (45deg timing).

The commanded afr can be as much as 2. out from what the wide band says. It gets closer as the computer learns the intergers - but after a chip burn say, it may take 10 miles before it runs at commanded.