* Weak: It might be able to prime, but unable to deliver sufficient fuel pressure at the required volume under engine load. This would lead to poor performance, hesitation, or stalling.
* Intermittent: It might work sometimes and fail at other times.
* Delivering low pressure: The pump may be producing pressure, but not enough for proper fuel delivery.
To diagnose the problem properly, you need to measure the fuel pressure with a gauge. A low fuel pressure reading, even with the pump priming, points to a bad fuel pump. Other issues that mimic a bad fuel pump can also exist such as a clogged fuel filter, faulty fuel pressure regulator, or problems within the TBI system itself. Testing the fuel pressure will help pinpoint the source of the problem.
