Quote from NealB. on April 1, 2023, 12:01 pm

Hi All

I have a Go EFI 600 on a 406 Chevy. When I fist set the engine up the FiTech did not control the ignition timing and all worked fine. I had the car this way for a year or two. Then I sent the car out to have the FiTeh tuned and the "professional" that tuned it changed the set up so the FiTech now controls the timing. The problem I am having is at what appears to be 2500 RPM exactly, I seem to lose spark for a half second. The tach drops down and the car kinda jerks forward from loss of power then after the half second everything works fine again. If I cruise at any other RPM I all is fine, it seems to be exactly at 2500 as I am slowly increasing speed when I drive.  If I just stomp on the gas it runs right past this point without noticing anything but I think that is just because I'm going past the problem quick enough to not notice it.

Any ideas as to where I should look.

Thanks for any help.