2002 Mazda MPV Intermittent misfire

Try cleaning or replaceing the MAF, seems to be the issue when you get surging, or "fishbite".

I cleaned, then replaced the MAF. Both options did not correct the problem. The good news is, my lovely wife has noticed a more accurate description of the problem. When she fills the van all the way up with gas, the problem nearly disappears. As the fuel level gets lower and lower, the problem gets worse. She does notice a fuel odor once in a while put can't place when or why. Her gas mileage has also gotten bad, about 18 mpg on average down from 23-24 when new.

The problem is like an engine stumble or misfire. It occurs in park or in drive, but is worse in drive and worse when the AC is on. This seems to be related to

I cleaned, then replaced the MAF. Both options did not correct the problem. The good news is, my lovely wife has noticed a more accurate description of the problem. When she fills the van all the way up with gas, the problem nearly disappears. As the fuel level gets lower and lower, the problem gets worse. She does notice a fuel odor once in a while put can't place when or why. Her gas mileage has also gotten bad, about 18 mpg on average down from 23-24 when new.

The problem is like an engine stumble or misfire. It occurs in park or in drive, but is worse in drive and worse when the AC is on. This problem seems to be related to the fuel system. Any suggestions?

If its a Ford 3.0L Duratec,check coils,pay close attention to wire harness on engine.Some Ford vehicles had trouble with harness rubbing thru either for coil or injector,especially passenger side rear on the engine. This could be A fuel delivery problem, check the pump pressure and line pressure, BOTH must be done Line Pressure is 55-61psi, Pressure hold after five minutes is 25.5psi test this way.

Fuel Line Pressure Inspection 1.Disconnect negative battery cable. Release fuel pressure. See FUEL PRESSURE RELEASE . Install fuel pressure gauge in fuel supply line. On all models except 626, Reconnect negative battery cable and go to next step. On 626, go to step 3 . 2.Locate DLC-1 on left side of engine compartment. Connect a fused jumper wire between DLC-1 terminals F/P and GND. See Fig. 2 . Turn ignition switch on and observe fuel line pressure. See FUEL LINE PRESSURE table. 3.Locate and remove fuel pump relay. See FUEL PUMP RELAY LOCATIONS table. Connect fused jumper wire between ground and fuel pump relay socket terminal No. 30. See Fig. 3 . Reconnect negative battery cable, to operate fuel pump. Observe fuel line pressure. See FUEL LINE PRESSURE table. 4.If fuel line pressure is high, check for plugged return line. If no problem is found, replace fuel pressure regulator. If fuel line pressure is low, check fuel pump maximum pressure. See FUEL PUMP MAXIMUM PRESSURE INSPECTION . If fuel pump maximum pressure is as specified, check for plugged or restricted fuel line or fuel filter. Repair as necessary. If no problems are found, replace pressure regulator. Fuel Pressure Hold Inspection 1.Disconnect negative battery cable. Release fuel pressure. See FUEL PRESSURE RELEASE . Install fuel pressure gauge in fuel supply line. Reconnect negative battery cable. On all models except 626, Reconnect negative battery cable and go to next step. On 626, go to step 3 . 2.Locate DLC-1 under hood. Connect a fused jumper wire between DLC-1 terminals F/P and GND. See Fig. 2 . Turn ignition switch on for 10 seconds to operate fuel pump. Turn ignition switch off and disconnect fused jumper wire. Wait 5 minutes and observe fuel pressure. See FUEL PRESSURE HOLD table. Go to step 4 . 3.Locate and remove fuel pump relay. See FUEL PUMP RELAY LOCATIONS table. Connect fused jumper wire between ground and fuel pump relay socket terminal No. 30. See Fig. 3 . Reconnect negative battery cable for 10 seconds, to operate fuel pump. Disconnect negative battery cable and fused jumper wire. Wait 5 minutes and observe fuel pressure. See FUEL PRESSURE HOLD table. Go to next step. 4.On MPV, if fuel pressure is not as specified, check for leaks and fuel pressure regulator. On all other models, if fuel pressure is not as specified, check fuel pump hold pressure. See FUEL PUMP HOLD PRESSURE INSPECTION . Also check for injector fuel leakage. See INJECTOR FUEL LEAKAGE INSPECTION . Fig. 2: Identifying DLC-1 Terminals Courtesy of MAZDA MOTORS CORP. Fig. 3: Identifying Fuel Pump Relay Socket Terminal No. 30 Courtesy of MAZDA MOTORS CORP. https://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm Go here and checkout our video.