I have same problem with a 99 Mazda Protege LX 1.6 Liter.
"Check engine" light came on. I took to dealership (for that and some brake issues). They promptly charged me $800 to make the brake grinding even worse and the "check engine" light fixed for 30days - at which time it came on again. I figured it was an automotive scam, so I simply ignored it. Been driving for 1yr with light on; Runs fine. But... recently I noticed gas mileage was getting much worse than my 300zx (v6), so I took it to Advanced Auto where you can get a FREE computer code print-out. You simply hook a little hand-held device to a port under your steering wheel, then take it back into the clerk and they'll print and tell you what codes mean. Mine said 2 fuel flow/emission sensors had gone bad - $200+ each! And the clerk said this would cause poor gas mileage issues.
Instead of spending another 4,5,600 bucks for this, I started Googling and found this:
"I have been a mazda tech for 16 years. There are most likely ports clogged in your intake manifold. first check for vacuum at the boost sensor (map sensor) the nipple on the intake can get clogged with debris. If that isn't it, you have the passages clogged in the intake with carbon. you can get to these through the throttle body-you may want to remove it and the egr valve, use a coat hanger, wire, whatever it takes"
...and also this...
"Service Bulletin: 1999 Protege:
TSB Number Issue Date TSB Title.
1. SSP056 FEB 02 Campaign - Mass Airflow Sensor Warranty Extension."
Does this mean this issue will be fixed as a warranty issue by Mazda? (it appears that way).
I can't believe you all are in my same shoes! And, to the last person, I printed out that very page and gave it to my guys at Merchant's Auto, and it still didn't do anything to get the check engine light to go off. To give you a history, I have a 99 Protege LX. Great car, up to about 1.5 yrs ago when the check engine light starting coming on. I noticed it would come on when the a/c was being worked hard. Then when the cooler months arrived, it went off on its own. When it came back on though, I was told it was my EGR valve. Got it replaced. Light came back on. Then they ran the diagnostic again and said it was the O2 sensors. Got BOTH replaced (to the tune of $660!). Car ran a bit better, but light came back on. Now it's flashing and it has really bad pickup. Again, I have kept this car in perfect condition, and now that it's got some age on it, maybe this accounts for the slower pickup. When I let it heat up a bit it runs pretty well. Long and short is - Can anyone shed light on this check engine light mystery that seems to be plaguing a lot of us poor folks??
I have read with interest the comments regarding the check engine light on the Mazda Protege series. I own a 1997 Protege DX, and over the past couple of years, have dealt with this check engine light with only moderate success. Seems like it pops on again every 3 to 6 months, with no rhyme or reason. It is a shame, because for the balance of my ownership, it has been a good and reliable car, but since hitting 100,000 over the past two years, the check engine light, along with sluggish performance, has dogged the vehicle. Oxygen Sensors ($400) and Intake Valves ($300) have been the most common reasons cited by the dealership, but the problem (check engine light) never seems to stay fixed for long. Does anyone really believe the Oxygen Sensors are dying every three months? I don't think so, but it is annoying not to have a clear-cut answer or a fix from anyone.
I own a 1999 Mazda Protege as well, I have 189 000 Kms on it. I love it, but I also have the check engine light on that started when I bought it when it had 70 000 Kms on it.
I also noticed that maybe 3 times a year, when I am driving on the Queen Elizabeth way, mid speed of maybe 80 to 100 kms, its like a jerking sound as if the car went into a lower gear immediately! It was almost as if it went from 4th geer to 1st geer! It would last a second and it would be normal again! And you actually jerked when it happened. I went to a transmission place and they could not find anything wrong with it. I have had the car for more that 3 years, and it hardly ever happens. The check engine light is an EGR Valve and I just disconnect the battery cable when it is time to to the E test here in Ontario. Does any one have this jerking problem?? Have always wondered what that was...
I have a 99 Mazda protege EX with the "Check Engine" light on. Auto zone read the code - P0171. The car runs good except for a rough idle. I noticed a little extra AIR noise under the hood; it could be air leakage at the intake manifold gasket. I'm taking it to a trusted repair shop this evening to let them take a look. You guys might want to check those air intake gaskets. Apparently www.alldatadiy.com has info on the faulty gaskets.
I own a 2000 protege 1.6 litre with 480,000 km (300,000 miles) and I use the car for delivery purpose.
Problems with flashing "O/D Off" light, and transmission shifting into 3rd or 2nd gear happen because the car's computer is switching into "safe" mode, like your home computer might in a problem situation. I solved the problem temporarily by checking the tranny oil level, and removing about a quart. A year later the problem returned. This time I had a free diagnosis (you have to determine if the problem is mechanical or electrical) and it turned out to be the T.P. sensor. Cost $200 but works perfectly now.
I was thinking of buying an OBDll Scan tool (for '96 and up vehicles) which usually sell for about $100. That way I can keep an eye on that "check engine" light that comes on from time to time. Anyone know if there are any problems or other information that could help?
I'm (somewhat) comforted to read all the previous comments regarding the check engine light problem in the Mazda Protege. I have a 1995 Protege LX with over 185,000 miles on it. The check engine light problem didn't become very frequent until a few years ago. The first time it happened, I took it to my local Mazda dealership, who diagnosed the problem as a bad air intake boot. That cost about $130 to fix and the check engine light didn't come on for over a year.
The next time it happened, I took it to an independent mechanic, who diagnosed the problem to be a bad sensor, which was replaced, and the check engine light was off for about six months.
When the check engine light went on again, I took it back to the same mechanic, who said that the car needed a major tune-up (replacing the spark plugs and wires). The check engine light was reset and stayed off for a few months.
When the check engine light came on yet again, the mechanic couldn't find a problem after running a diagnostic check, so he just reset the check engine light.
Just this afternoon, while I was driving home from work, (you guessed it) the check engine light came on. The car is running fine otherwise. I've decided that I'm just going to let the light glow, as long as the car runs fine. I'll have it looked at the next time I bring the car in for service. It's just too bad that this is a continuing problem, because other than that, the car has been VERY reliable. Based on this experience, however, in all likelihood, my next car won't be a Mazda.