Hi Simon,

If it had been a late 80's Accord then I would have said check the mechanical advance weights in the distributor as they were probably stuck, but this won't apply on this ;-)

Have you checked the timing with the two pin SCS connector shorted as this should set it to base timing mode. Has the cam belt been changed? Perhaps check the cam timing given possible low vacuum. Also, the inlet valve clearance can go tight causing vacuum problems, but not usually this bad.

HTH

Sean