I have a 2000 Maza Protege with 99,000 miles. In the past few months the check engine light would come on, then go off. The car ran fine. Then when it finally stayed on for about a month, it started having a "funny" smell, like it was running too rich and from time to time at lights, it would act like it was going to stall out. The idol dropped low and started running rough. And when we began to take off, it would act like it didn't have any power. I took it to AutoZone to have the codes read. They said it was running too rich and it could be the O2 sensor. I replaced the O2 sensor closest to the motor with one of the universal sensors. I also replaced the spark plugs. I took the car out and drove it about 5 miles, the check engine light stayed on, so I unhooked the battery to clear the codes. Now the light is off, and we still have the same problem and it seems to be getting worse. Today, my wife drove it and the symptoms were more pronounced and she said it sounded like it 'farted'. I think she meant it might have backfired. I took it back to AutoZone and they said there were no more codes to read and to replace the spark plug wires, which are on order and will be here Saturday. Do you think this could be a fix? Any help would be greatly appreciated!

 

Have you taken it to a mechanic or a Mazda dealer? One thing that you may have to do is get the engine idle re-set. A few years ago, we took our Protege' in to have the battery replaced and when we tried to drive it, the idle was all out of whack. At times, the car almost stalled. We had to take it to get the engine idle reset. It seems that disconnecting the battery whipes ot the computer's memory and certian funcitons like your radio presets and the engine idle have to be reprogramed.

 

this year and symptoms also point to the mass airflow meter-this also has an extented warranty from the dealer-hope this helps

 

I know nothing about cars, but it sounds like what happened to mine. I had to have the EGR valve replaced. My check engine light was on, it was stalling at stop signs, and would lose power randomly when driving. So maybe??????

 

The description sounds very much like contaminated mass air sensing wires. There is a warranty extension but it is only for 7years or 70,000 miles which you are obviously past at 99k. Does your engine have the 1.6l or 1.8l engine??? The 1.8l has a recall on the ignition coil for breaking down and loosing spark which may be the case. If so this recall is still active unless yours has already been replaced. The mass air flow sensor problem was only on the 1.6l engine. The wires that detect the amount of air flowing into the engine get covered with a black soot so the reading sent to the computer is not accurate. Replacement is the best option and can be done at home with a phillips screwdriver. I have cleaned quite a few and had very good repair rate doing this. If you will post your vin number I can check to see what engine you have and also if any recalls have been done

 

I have a 1999 Protege LX with 1.6 engine and it has this recall (it's listed on my Owners' homepage on mazdausa.com based on the VIN number), it says:
1999 - 2000 Protege 1.6l Eng. Air Flow Sensor Warranty Extension To 7 Years / 70,000 Miles
I am the original owner, but when this recall came out in 2002 my car was already at 80,000 miles and so I ignored it. The Check Engine Light was sometimes on for a few month, then off, but there was no noticable effect otherwise. And because the light just happened to be off at inspection times, it always passed and the measured emissions were always low, so I'm sure it's the sensor problem, not an engine problem.

Now the car has 120k miles and it's inspection time again and the light is ON. I can turn it off by removing the battery, but by the time the checks are complete, the light comes back. I have an OBDII reader and that says:

P0171 System Too Lean (Bank 1)

What is the cheapest way to fix or change this sensor? I'm afraid that if I take it to the dealer, the bill will be more than the value of the car. The car otherwise runs fine, so I'm not looking for a "repair", just something that makes the erroneous reading go away.

Is there a manual about where this sensor is and how to change it myself?

Thank you!