Hello everyone! About 3 months ago I did the 50K mile service on my 2nd gen. Protege LX and about 2 days after that my "check engine" light came on. Long story made short -- I brought my car to a service and they diagnosed a "misfiring 4th cylinder". They advised me to replace the distributor cap, dist. rotor and the ignition wires. They also suggested a "tune-up" costing $59. The total price came to $285 ($147 for wires alone!!!). I changed the stuff myself and paid about $100 for parts (including spark plugs, which were not recommended by the service). Well, I changed everything the mechanic would have changed and my car still has a rough idle. It looks like the 4th cylinder is working OK on high RPMs, but when the engine is idle it runs rough and even removing the wire on the 4th cylinder makes no difference!

My question is: Should I go and spend $60 for a "tune-up", or that's something I can do? I have a friend who can help me out with the OBDII... He has a laptop with the cable that hooks up to the OBD and all I need is the software for my car. If there is such software, where can I find it? Is it available?

PS. I was looking for numbers that resemble error codes and this is what I saw on the report sheet:

6953
P304
4th cyl. misfiring

I hope it gives you a clue.

Thanks a lot guys!

 

ok it sounds like you have a problem in you ing system for plugs or wires. i would rec cap and rotor as well its easy to do a couple of screws and your there make sure you put the rotor on the same way in came out. any probs let me know!

 

I already stated in my original post that I have REPLACED the rotor, cap, spark plugs AND wires.

 

Are you sure that you replaced the rotor cap the way it should be, because if you put a new one back in the wrong place, you will still have that cylinder misfire. At 50K, you do not need a tune up, I don't even think you needed the wires either, because you have replaced them, and the problem is still there.

 

I placed the cap and rotor exactly like they were on there originally. And YES, I know I did not need the wires but I replaced them anyway... What else?

 

OK, I cannot think of any thing else as of now, but I will ask my boss next Friday(I work at Speedy's), and I will let you know. Good luck.

 

Should I go for that tune-up? I mean, I don't mind paying $60 if it'll fix my car? It looks like my car is running on three cylinders at idle, but I don't see any performance difference at 2K-3K RPM. It runs OK, doesn't die on traffic lights... What the hell is wrong with it?

 

I figured that the actual code is P0304 and this is what it means -- Cylinder #4 Misfire Detected.

 

Any more input? C'mon guys...

 

I had a tercel that when I removed one of the plug wires..there was no difference in engine idle...I think at high rpm's you don't notice ,but the cyclinder is still not running right...tercel had dead cyclinder...i.e. either the valves were not closing all the way allowing no compression/misfire or the rings could have been bad...I adjusted valves but it made no difference...I wouldn't waste money on tune-up...could be dead cyclinder=dead engine=buy new car or replace engine...how many miles?

 

I would also check firing oreder since u replaced wires, spark plug tightness...could be loose...don't strip it though.....do a compression check on cyclinders...25 dollars at store...compression tester threads into spark plug hole...if cyclinder shows low or no compression...engine is proably fucked

 

Can no one read through the whole post before replying? his car has 50K miles. Spend the $60. If anything it will give you the actual problem instead of guessing.

 

can ne1 read the post...BLAH BLAH BLAH...50K service doesn't mean 50K miles on car...it means a 50K service... : )

 

Thanks for the interest everyone!

First of all my odometer says 56K.

I went back to the garage and told them that I changed everything they recommended, plus spark plugs. One guy there told me that Bosch spark plugs are know to cause problems with Japanese cars(???). He said that his family has two mazdas and they had problems with Bosch. I am using the platinum version, but it's the basic one...... (not the 2 or 4...). So, I went there (Good Year Tire Service on Fremont Blvd. in Fremont, CA) and told them what I've done to the car. I also told them that I replaced only the 4th cyl. wire since it's the one that misfires, and they said that they will replace the rest of the wires if needed. I got a call an hour later and the guy said that my car is fine now. All they did was change the rest of my wires with news ones (I had the rest in a box in my trunk). They charged me nothing since I already paid $90 for diagnostics the first time, so I got in my car and started the engine. I was surprised when I didn't feel this rough idle I usually experience. I still had some rough idle when in D (I have an automatic), but I think that's normal. I drove about 10 minutes to my place and parked my car in a garage. It ran smooth and I was happy to have my car finally "fixed".

About 3 hours later, I had to go to school, and surprisingly, my car developed the same problem as before. About a minute into my ride, I had to stop at a traffic light and felt this rough idle again (rougher than usual). At moments like this I really think that the 4th cyl. is gone. There's this sound coming from the exhaust... I can't describe it very well, but it's something like ... ta...ta-ta-ta ... ta...ta-ta-ta.... lol So, I had stayed for about 10 seconds at the traffic light and the check engine light started to blink. It blinked for about 10 seconds and became solid.

After school I went back to the Good year... service and told them about the problem. They said that they can't do anything right now, but will look at it tomorrow. So, I made an appointment for Wednesday (they said that their best mechanic will be there on Wed.). At that moment, that same guy who told me that Bosch spark plugs aren't good for my car told me that his family had to replace some part on their two mazdas at the same time - at 60K miles. Some mechanic at some dealrship had told him that the part in question was really supposed to work for 60K miles - not more. That seems like crap to me, but ..... whatever. The part he was talking about is the "airflow meter sensor" or something like that. I'm guessing it's the one after the air filter? I don't think I got the name right, but you guys should know what it is....

SO, could that be causing my problem or the guy is sending me on a wild goose chase?

One thing to add... Someone else has told me that K&N filters could cause the above mentioned sensor to fail. Is that true for our Mazdas? If not, could the K&N filter be causing my problem?

I'm sorry for the lenghty post, but I hope to resolve this. The car isn't that old.... Please help guys!

 

Like I promised you, I asked my boss at work, and he said to look more carefully again at your spark pluges. They HAVE to be gapped right, and they cannot be overtightened or too loose. Take them out, make sure the gaps are within the limits, see if there is any damage to them, and carefully put them in. The wires should not cause misfiring, and neither would your rortor cap, that would make all of your cylinders to misfire and all hell would brake loose.

I have 60K, on my car, I have K&N filter, and I changed my plugs at 30K (Bosch Platinum), I also just cleaned my fuel injection system with Castle 3-Step, and I never had a misfiring or anything closely related to that. My wires are stock by the way.