My fuel pressure drops from 30 psi to 10 psi in half an hour and then stays pretty constant. Is this normal or is something wrong? Is it my injectors or fuel pump? Is there a way to find out exactly what is wrong.

 

While its running???!!! That would not be good.

 

Sounds as if either the pump or fuel pressure regulator are acting up when hot. If the pressure guage is right, it's a wonder it will even run at 10 PSI. You can eliminate the regulator by doing the following. When pressure drops, leave engine runing. Take a pair of pliers and carefully crimp the fuel return hose to the gas tank. If the pump is OK, the pressure will increase very fast. If pressure remains low, there is a very good chance that pump gears are worn and expanding when hot. Pump will need replacing. If pressure goes up with hose crimped. The regulator is probably bad. Check engine vacuum cold and hot. This controls the FPR operation. Maybe this will help.

 

Just to clarify one thing when I turn the engine off it is at 30 psi but after half an hour it drops to 10 psi. While the car is running it stays at a constant 30 psi with the vacuum line connected and 42 with it disconnected. Should the pressure drop off like this once the engine is off?

 

I think 1/2 hr is a decent leak down time; not to worry.

 

so this would be normal? do I have anything to worry about?

 

Your guys are saying that 10psi is normal? No, it should be up about 47 psi at idel stock. Most people bump the pressure up to about 50-51 on a stock car. I would say you might have a problem.

Do you have any problems when you acelerate? you might have a weak pump. what are the specks on your car?

 

He's saying that it drops from normal to about 10psi after the motor has been Off for about 1/2hr. That seems like a normal leak down rate to me, at least not to worry about.