For the past three days, when I start my Mazda 6 2005, it revs to 3 or 4 slowly going down to normal. Then, without even pressing the gas, it changes gears. The fuel pump is not the problem because the car has power and wants to move. When I opened the hood, I noticed that the front o2 sensor was glowing bright. I brought my car into a Mazda dealership and they hooked my car up to check the pressure of the fuel pump and it was fine. Then they hooked it up to the computer to see if they can get any readings to see if it would show any problems but nothing. They think that it could of misfired due to the coil but they are not sure. They said that there could be a crack in the coil and water got into it or the coil is just breaking down. OR they said that it could be a glitch. I find when the car begins to act up, if I turn the car off and restart it again, it works fine. Please help.

SOURCE: Mazda mx3 wont start

VSS or vehicle speed sensor aka cam sensor or crank position sensor. Test the battery and alternator. You should also check for blown fuses, bad wires and grounds on a car as old as yours. If you find it's getting spark and fuel after further testing, check the timing belt. It could have slipped or broke even if it was changed recently so either pull off the cover or at least do a compression test.

SOURCE: 98 mazda b2300 truck wont start.fuel problem.

i would try replaceing the fuel filter frist.then i would un hook the fuel line and see if you got gas to the fuel filterthat will tell you if your fuel pumpis working or not . ok good luck

SOURCE: 2002 Mazda Protege acceleration problem

I had the same problem and found that the air admission tube was badly cracked.

Since this let air enter the engine downstream of the mass airflow sensor it is not measured so the engine ECU don't send the proper amount of fuel to provide the right air/fuel mixture. At higher RPM, the vacuum in the tube is enough to close the crack and hide the problem.

I temporarly repaired it with duct tape until I get the part.

Stephane

SOURCE: 1992 mazda mx3 is overheating. checked thermostat

Check your coolant. If the coolant is low, you won't get heat in the cabin. Make sure that the fan is turning on as well. Check coolant sensors also. Good luck!

SOURCE: 95 Mazda b2300 ( Engine code p0320) misfire cyl 2

check the feul injector on that cylinder. use a stethoscope to listen to it. injector should make a clicking noise as it operates. if it doesnt click, check the wiring at the terminal. if the wiring is ok then apply a 9 volt battery to the prongs on the injector to check if it is working or not. if the injector for that cylinder is not operating properly then the cylinder will missfire. if the injector and its wiring is good, check the valve clearance with a feeler gauge and adjust if necessary. if the valves are good then test the compression of the cylinder.