Mazda Protege CEL problems...

[kasruesao]

Hi, so I've had my 2003MP since May. The first few months, it ran great. And every so often the CEL would come on steady and then turn off by itself. My dad's mechanic friend replaced the spark plugs...I would say...2-3 months ago?

I believe a few months ago, I was driving long distance (half an hour away on highways) and when I was at 55mph, the car sputtered and slowed down to the 40smph. The CEL was blinking for a few minutes and then turned steady. I spoke to my dad about it who seemed to be very nonchalant about it. -.-

So I've had a steady light for a month-month and a half when I was dropping someone off and while I was stopped at a stop sign, my car started to vibrate/shake and the CEL began blinking. When I turned it on a while later, the light was steady.

I went to an Advanced AutoZone and had codes: P0300, P0421, and P0090 read. -.- I've been looking long and hard for solutions online and my father's mechanic friend will be looking at it when he gets the chance.

This car is the only car my family owns and I'm the only one who drives so you can see my concern. When I started the car on a cold start this morning, it was vibrating and the CEL was blinking when I was letting it warm up. SIGH. What to do? My family member is due at the doctor this Thursday which is a half hour away (and the only reason I really ever wanted a car was to help out).

So if you could provide some guidance, that would be goooood.

Thanks.

 

[kasruesao]

The car is also around 100,600K miles. We just changed the oil a month ago.

 

[HLSilver Es]

My 2 for what it's worth:
The P0300 is a random or multiple misfire IIRC. Most likely either plug wires or a coilpack. Coilpack failure was fairly common on 3rd gen Proteges.
P0421 is for the catalytic converter or the downstream O2 sensor. Depending on the emissions laws where you live you could do the non-fouler and get rid of the light, otherwise you'll most likely need to replace the cat/sensor. I had this code for a while after replacing both O2 sensors and where I live I don't have emissions so I went with the non-fouler, cheaper and it works fine.
Not sure what the P0090 is, Google said something about low fuel pressure. From what I read (skimmed over rather), this code may possibly cause the other codes so I would track down a solution to this one first.

 

[concept]

...lots of good info, here:

http://repairpal.com/OBD-II-Code-P0300

...which may have caused this:

http://autotips101.com/cms/automotive/obd2-codes/p0400---p0499-auxiliary-emission/obd-code-p0431.htm

And this being related, somewhat:

http://www.justanswer.com/mazda/3xx...ine-code-egr-valve-replacement-are-codes.html

 

[ehsande]

I just bought a 2003 Protege5 a few weeks ago with ~80,000 miles on it. I was looking up various issues to watch out for and came across EGR valve clogs that can cause the symptoms you describe. The carbon buildup can be cleaned out, but the part was $75 on Amazon so I figured why not start fresh.

I got the part and intended to put it in myself, but had to work out of town for a week and figured it could wait. The day after I left my wife was driving and the car began losing power, CEL flashing - all the classic symptoms. She managed to get home and I arranged for her to take the new EGR valve to a shop to be installed.

Here's a link to a photo of the old EGR with carbon builup:

http://www.flickr.com/photos/48379912@N05/11223198534/in/photostream/

Been running great since having it replaced.

 

[concept]

Now that's a lot of carbon buildup!

 

[thuzil]

Replace your coil packs. You can also replace your secondary o2 but this is not really necessary for the car to run.

 

[kms1990]

if your fuel pressure reg. switch or sensor is out that can be your issue alone, i would start there low or unregulated fuel pressure can cause your other symptoms