Engine stumble when applying power for takeoff around 2200rpm

[1964-M20E]

When adding power for take off my IO360A1A has developed a stumble.   This is as going from idle to full throttle and happens around 2200rpm but clears up as the engine gets to 2500 with or without the boost pump.  During the engine run up there no issues.  I have cleaned the injectors, intake screen on the fuel servo and the collator is clean.  All intake tubes seem to be good.

It sounds almost like it's lacking fuel during that throttle phase similar to advancing the throttle when leaned on the ground.

 

Any ideas?

[Rwsavory]

Do you have engine analysis data to share?

[Jsno]

Could be your engine driven fuel pump.