Throttle response delay
 

Today I noticed a split second delay when I quickly throttled the engine. I pulled over and from idle when I hit the gas quickly I have a delay before the engine revs. Its a quick delay and not sure how worried I should be so I thought I would post the symptom to see if anyone has dealt with this before. Kinda hard to replicate when driving as I can't get the revs close to idle and throttle up quickly so mainly, I can replicate from idle in neutral.

1990 C2 with 49K original miles. Engine has never been out of the car and never torn down. I run 90 non ethanol gas and VR1 oil. 5 speed. Last time I went through plugs etc was 2K miles ago. Thanks