Hi all, some knowledgeable help would be awesome!

[Javid]

Hi all, I own a manual transmission 2002 Mazda Protege. Its been a great car since I got it, but recently I've run into some issues and I figure the smart people here might have some clues.

Here's the situation:
2 weeks ago I started up the car and it ran fine but I noticed the check engine light was suddenly on.

1 week ago I finally got around to an auto parts store and the OBD reader was unable to connect to my car. (weird)

3 days ago, I disconnected the battery for a few minutes to reset the computer.

I started up the car and the Check engine light was off, but at high RPM in first and second gears, the car would lurch a LOT. Almost making it impossible to get up to speed to upshift to 2nd or 3rd. Sometimes it lurches a little in 3rd, but 4th and 5th are fine as far as I can tell. (Its almost as if the engine is getting a lot of gas for half a second, no gas for the next half a second.)

Today the check engine light came back on, the OBD reader worked, but the error code is P0131. Checking online, it seems like this error code is associated with just being an annoyance and not actually affecting the car performance. Maybe another code will show up if I drive more, but I dunno yet.

I'm competent at taking things apart and such, I replaced my own oil, but I am not a car mechanic.

Any thoughts or suggestions would be much appreciated. The weirdest thing was how the real problems started right after disconnecting the battery, that makes no sense to me.

Thanks for any thoughts you might have.

 

[Jackie chan]

P0131 is a code for your upstream oxygen sensor and it is definately your problem. Without that o2 sensor you're no longer seeing your afr. Your ecu is just guessing how much fuel it needs.

 

[xxxmonoxidechil]

Agreed, Thats a bad O2 sensor. And could definitely cause the exact issues your experiencing. Replace the O2, and the problem will most likely be fixed.

 

[Javid]

Alright, makes sense to me. Thank you so much!! One more question before I start:

I found this guide: http://www.mazdas247.com/forum/showthread.php?123819066-Oxygen-Sensor-Change-with-Photos

The guide looks like something I can do, but I'm having trouble finding where to buy the sensor itself. The guide mentions a "denso" brand for about $30, but my local o'Rieleys has parts between $60 and $220. I see here at rockauto a bigger selection: http://www.rockauto.com/catalog/x,carcode,1430264,parttype,5132 , can I just choose the cheapest "upstream" part listed here?

Basically, I need a link to the cheapest, moderately reliable part that will work for my 2002 Mazda Protege DX 2.0 Liter. (I doubt the car will last another 12 years.)

 

[concept]

I would spend no more than $40. That APWI Part # AP4202 is what I'd get.

 

[CoTa]

Check for vacuum leaks. Leaky vacuum can cause incorrect afr.

 

[Javid]

Hi all, you have been so helpful. I replaced the Oxygen sensor and it was still pretty bad. Just yesterday the Check engine light finally went on again, so I got the code checked again and it was the same P0131 code!!

I just noticed CoTa's post about checking for vacuum leaks.

I checked out my car and found huge gaps in the Air Intake hose. (Does that count as a vacuum leak?)

Letting the car run and messing with the hose I could get it to run a bit better by squeezing it (closing the holes) and can make it almost stall by stretching it, so it seems to be the problem.

The intake hose says FP47 on it. I also found Dorman 696-601 as a replacement part.

I found one on amazon for $25, and that sounds fair to me. (Better than $50 nearby)

Hopefully this will fix my problems, and hopefully my plight will help other people with this problem.

 

[hornsfan10609]

Glad you found it, that is probably the most common issue on proteges

 

[xxxmonoxidechil]

Vacuum leaks and turbo cars dont go together. Glad you got it all figured out.