Nissan Repair: 1986 nissan 300zx 2 2 fuel problems, fuel pressure gauge, fuel pressure regulator

Question
I have a nissan 300zx and we accidently let it run out of gas one day. When that happend it first started to crank but you have to pat the gas peddle to keep it running. When you let off or put in gear it dies. We changed the fuel pump and the fuel filter and it will crank and idel real good but when you give it gas it dies and now it wont crank at all. It smells like it is burning rich! Please help Please. Before this happened the car ran close to perfect.

Answer
Laura,

You either have a fuel pressure regulator that is gone out or an injector or two that have stuck open.  To check the regulator get a fuel pressure gauge and then hook it up and with the engine running unplug the fuel pressure regulator vacuum line.  The pressure should go up 15 to 20 psi.  If it stays the same the regulator is bad.  Then, turn off the engine and note the fuel pressure.  If it drops off really fast you have injectors stuck open.  If this is the case pull the spark plugs, noting which hole they came from and the ones that are really black are the cylinders with stuck injectors.  If it were me I would replace them all if a few are bad since you do not want to do it more than once.