hard start 87 944 need help

[shannon]

New 944 owner having trouble getting car to start again. Car has sat several years. Car started after cranking minute or so ran prettywell all things considered. drained gas tank,replaced fuel filter. Car started again after minute or two of cranking. Ihave 40 psi at fuel rail when key is switched on, 40psi when car is at idle,about 1k rpms. pulled vac hose of fpr no change to idle. Clamped return line car dies within 2 or 3 seconds so I couldnt check for rise of pressure to 60psi. Fuel pressure drops to 0 as soon as i turn key off, doesnt bleed off slowly. while car was running I pulled each injector off and idle stumble as would expect from 3 cylinders. Cant get car to restart. Jumped 87,87b and30 on dem, replaced fpr but believe with s model because pressure at rail jumped to 60 but it did bleed of slowly put old fpr back on back to 40 at rail. pulled one injector off to reduce pressure still wont restart. I have vac leak on#1,2,3 cylinders intake manifold gaskets. Ordered another fpr,intake gaskets and fuel pump check valve. Tach moves slightly while cranking, and I have good spark to all plugs. I enclosed about everything I colud think of that I tried. Waiting for parts, running out of ideas

[SoCal Driver]

Replace the check valve at the fuel pump outlet.

Fix the vacuum leaks.

[Zero10]

Fuel pressure should not immediately dump to 0 when the key is turned off. You need to figure out where the fuel is going.
Hugh has a very good suggestion of it being the check valve located on the fuel pump.
The other possibilities are a bad fuel injector or a malfunctioning FPR. 60psi is far too high at the fuel rail and it sounds like that is the wrong FPR. However if it fixes the fuel pressure falling to 0 on shutdown problem I would follow up and replace your FPR with the correct one. That is, unless I mis-read your post.