check the tandem valve is operating properly. if you take off the top
off the throttle body, you can see it operating like a choke - it should
open when you open the throttle.

there's a piece of vacuum hose that runs from the tandem control valve
[at the bottom of the throttle body] to the tandem diaphragm. if this
is cracked & leaking, you'll have exactly the problems you describe
because the tandem is not opening fast enough and the valve is choking
off air supply to the engine during acceleration.

Thien-Anh wrote:
> Honda Civic DX 1990
> I changed an used distributor about two years ago. I have a one-month new
> clutch and all my valves are adjusted. My water pump and timing belt are
> about two years. My car ran smoothly for the first week after adjusting the
> valves, but the same old problem occur after that. The problem is that when
> I press on the gas pedal unexpectedly, it does not accelerate immediatelly.
> Some times it does not even accelerate. The engine is reving, but no
> acceleration. I took to so many mechanic, but no one knows what causes it.
> Any one has similar problem, please share. Thank you.
>
>
>