Miata stall on down shift
 

My 1990 Miata is stalling during deceleration or down shifting - like approaching a stop. I have had it professionally serviced, but the specialist had not found the problem on test drives. It is intermittent, but now is almost constant.

Anyone have ideas on the source of the problem? Like maybe the fuel pressure needs to be boosted??

Currently, the idle is at 900 rpms, and the plugs, wires, timing belt, etc were done 6,000 miles ago. It has been garaged and is in very good shape other wise.

Bruce VZ