A number of issues can lead to irregular fuel pressure. If your measured value does not match the values specified in the factory manual you should first run the test again, paying special attention to any possible leaks in the fittings. If you are still getting abnormal readings here are a few potential culprits that may warrant further investigation:
| Low Pressure |
|---|
| Leaks in the fuel line |
| Fuel pump issues |
| Fuel pump wiring, fuse, or relay issues |
| Upstream clog in fuel line or filter |
| Fuel pressure regulator failure |
| Leaking fuel injectors |
| Low fuel level in the gas tank |
| High Pressure |
|---|
| Obstruction in the fuel line or rail downstream of the tester |
| Clogged or obstructed return line |
| Kinked or pinched return line |
| Fuel pressure regulator failure |