have an '89 iroc-z 350 tpi, usually takes about three tries to start. pump works fine, new match flowed msd injectors (22 lbs.) put fuel pressure tester on it& got 50 psi momentarily with key on. pressure dropped to 47 psi and slowly faded to about 12 psi. with engine running pressure holds at 40 psi. checked fuel lines under hood. no kinks, fuel leaks, or fuel smell. also changed fuel vent valve. think i might have a pinched fuel inlet line somewhere. any suggestions?

I had a pump do that to me once and replaced it. Also had a plugged fuel filter. Owned many a TPI.

Pinch off the pressure and return hoses with fuel pressure in them.If the pressure drops,the injectors are leaking.If it holds pressure,drop off the pressure side clamp.If the pressure drops,thecheck valve in pump is leaking.Do the same on the return,if it drops,the regulator is leaking.

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68 z28 ,68 rs 327 ,73 454 vette, 2 goofy kids