LQ9 with a Holley 4BBL conversion and 6014. Runs rough between 1,200 & 1,500 RPM. Very smooth otherwise. Tried two different carbs, no change.

Just installed Holley Sniper EFI. Runs better, but the roughness is still present. No vacuum leaks, 20 inHg. Coolant sensor not hooked up at this time.

When on read only, timing looks to be in the correct range. Any ideas? Thanks.