Bogging problems with Silvertop 4AG (BT ECU) under 3500 RPM

[LAC99]

I have a problem with my silvertop 4ag when it revs from idle to about 3500 RPM. I didn´t know how to describe it in english but someone just told me it´s called "bogging" (sorry for my english, by the way).
Anyway, it has a Blacktop ECU and MAP and the thing is that below 3500 RPM it has this bogging problem that I can´t get rid off. I´ve tried replacing the ECU with another BT ECU, changing the module, new wiring harness and also changed the TPS but it still does that bogging thing.

from 3500 to 8000 (according to my SAFC) it works perfectly but below that is really frustrating, specially if I give it full throttle because the engine starts knocking a little bit so I have to let go a little.

I don´t know if this helps you get a better picture but when I let go a little bit the throttle it actually revs better than at full throttle. That´s why I thought it was the TPS sensor but when I changed it, I had the same problem.

any ideas? I don´t have a oxigen sensor connected but I thought the SAFC would solve that.

thanks