'90 Integra has what I would describe as a flat spot upon gradual acceleration. It's not hesitation as you know it - just a partial throttle flat spot where nothing happens. I can't pin-it-down to any particular RPM.
Can't find any vacuum leaks. Fuel filter age is unknown but it has no other typical symptoms of fuel filter trouble. If you mash the throttle or accel rapidly, it's OK.
Timing is dead-on at the factory recommended 16 BTDC.
I just freshened the head/valves - replaced a burnt exhaust valve. Intake/Exhaust valve clearance set to .008.
I'm going to look again for a vacuum leak but.......

Any thoughts?

 

dont just look for a vacuum leak, get a meter and test it. try to get a new filter theyre cheap, replace oil etc. and just gereal maintainence

 

Ok...what am I testing with the meter?