2001 Mazda MPV sputters at 5/8 tank full

Maintenance/Repairs
1

Car runs fine from full gas to 5/8 tank, then sputters. Refill gas, runs fine… Repeat. What the heck!!!

2

Is your check engine light on? Also, do you stop pumping when the gas stops or do you top off? I wonder if your charcoal canister is saturated…

1 Like
3

The next time this happens, remove the gas cap, put it back on, and see if that makes a difference. If so, let us know.

1 Like
4

I top off. Light comes on and goes back off intermittently.

5

The fuel pump is starting to fail.

When the gas tank is full, the level of gas in the tank provides what is called a head pressure. This head pressure assists the weak fuel pump to provide the proper fuel pressure/volume to the fuel injectors.

Then as the level of gas in the gas tank decreases, the head pressure decreases where it no longer assists the weak fuel pump. And the engine starts to run rough.

Fill the tank, and the engine runs fine.

By the way. Since OBDII, you cannot overfill a gas tank where it damages carbon canister.

There’s a component in the EVAP system called a roll-over/over-fueling valve that prevents that from happening.

Tester

1 Like