26th Apr 2006, 09:08

I purchased a 1999 Protege new which now has about 63,000 miles on it, and I have only had 4 problems over the past 7 years:

1.) P0420 - catalyst system below efficiency

2.) P0171 - system too lean. These two messages seem to come and go. I'm currently investigating the problem. After reading all your comments, it sounds like the Mass Air Flow sensor needs to be cleaned, or an O2 sensor (bank 1) needs to be replaced. I'm also considering changing the fuel filter while I'm at it, and checking the vacuum/hoses for proper seal. I'm not sure why else there would be too much oxygen in the exhaust? Hopefully this is not a more expensive problem like the catalytic converter.

3.) Heat shield. Comes loose and makes a terrible rattling noise, but is simple to fix (just retighten it).

4.) Tires. I've gone through 2 sets of tires in 60K, and I'm not driving on bad roads. Perhaps I just have bad luck.

I recommend everyone purchase an ODB2 reader, you can find a decent one for $40-50 that will let you read/delete the CEL messages yourself. Or just stop in at any mechanic or oil change place to find out what the message is, then research it on the internet (like we're all doing now). Taking it to the dealer is probably a last resort because unless you have a major problem, it's usually unnecessary and will be the most expensive repair option.

I've experience no drivability issues with the P0420 and P0171 errors. It's probably some combination of low fuel pressure (dirty filter?), sensors (MAF/O2), or carbon buildup. If I find a root cause this weekend, I'll post again.

27th Apr 2006, 05:47

Anybody familiar with P0106 : Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance problem?

I have the check engine light on constantly, but it sometimes disappears for hours at a time. The car runs perfectly- smooth as can be.

I have removed the EGR valve, solenoid, and booster. Lubricated and cleaned all attachments where air would pass through. The hardest to clean was where the EGR valve is attached to, the manifold, and there's a small 2-inch tube sticking up vertically. I had to drill through to clean the build-up of carbon.

I tried going to different mechanics, even an electrical, but all they want to do is replace parts.

I figure, if the check engine light goes off and on, then the parts must still be okay. Otherwise it would stay on all the time.

2nd May 2006, 13:04

I have a 1999 protege, with 105k miles. Recently, the car has started to idle roughly, particularly when it first starts up. It runs fine when it's moving around. Rough idling causes the car to die about 10% of the time after startup.

The infamous check engine light has been on for a long time (over 1 year). Last time I had it looked at, it was the "running lean" error, so I figured as long as it ran well, no reason to get worked up about it. I have a suspicion that a sensor is bad now, however. Any thoughts?

3rd May 2006, 08:00

That check engine light continues to haunt me.

I managed to get rid of the light for about 4 days, by removing the EGR valve and cleaning it thoroughly.

But now, alas, it has returned.

I'm now thinking maybe the intake manifold should be cleaned out? Big bucks for that. Or is it some other electronic sensor/device that is malfunctioning?

4th May 2006, 08:25

Replying to : '99 protege with 105k miles; rough idle and car dies sometimes.

Have you checked the "coolant sensor" yet?

Here's a few of the symptoms: Poor cold idle, stalling, cold hesitation, poor fuel mileage, rich mixture, etc.

10th May 2006, 09:16

I bought a used '98 Mazda Protege about 3 years ago with 100k miles. Has been very reliable. About a year after purchase the check engine light came on. Went to AutoZone and had the codes read and was told it was a gas cap issue (gas cap was not on tight enough). After adjusting the cap, the light went away for a while. The light would come on and go off intermittently and the only thing I could figure was it had to do with a change in the weather (on dry days, no light, on wet/humid days, light came on).

I live in Austin, TX where the state vehicle inspection was just changed to include auto emissions testing. They will not pass you if the check engine light is on. Needless to say, I had to take it to a mechanic where I was told the O2 sensor and EGR valve needed to be replaced. Was also told these parts had to be ordered from the dealership and cost ~$900. Bit the bullet and had the work done. The light stayed off for one day. Took it back the mechanic and had him perform the inspection. Next year, when I have to inspect the car again, I have to go back to this mechanic to have it inspected because he is familiar with my "special" car.

Someone has suggested the light is a ruse to get me to take the car to the dealership (it comes on automatically at 100k/120k miles).

Conspiracy theories aside, I wish I knew what to do. I like the car, but can't afford to spend $1200/year to have the car inspected.

12th May 2006, 07:36

Well, I'm not sure if it's a ruse or not, but the check engine light goes on about every 100K, because it's programmed to do so. Many auto-makers specify that the timing belt should be changed every ~100K. But anyone that has long-term experience with vehicles, will tell you that's not true at all. I had another Mazda that lasted about 700K, and I only changed the belt once, at about 500K. Since The Protege is the "non-interference" type engine, you can wait for the belt to snap and then replace the belt (just make sure you have a cell phone, and belong to an auto-club).

I don't know if it will help you or not, but you know that if you disconnect the battery, for over 2 minutes, that will reset the check engine light.

Depending on your car's problem, the light will remain off from 1 hour to a few days.

30th May 2006, 17:29

HELP!! I have a 99 protege 1.6 liter 5 speed transmission and had it for about 2 years now my check engine light came on had the code pulled-bad O2 sensor-any how drove it like for about 6 months then it went out. Now it came on again different code running to lean or something. Cleared it new code popped up, manufacturer air fuel something. Well done a tune-up replaced the coil packs, new O2 sensor, and cleaned the throttle body out. heres the problem it hops, spits, sputters, bogs, and hesitates when accelerating and driving.

So anyone know what it could be?