Check Engine Light (PO300)

[mp5wgn]

Hey there... i'm here 'cause of a problem. I have a 2002 Mazda Protege 5 (2.0L) w/ 78000 miles. For the past couple of weeks, i've been experiencing engine trouble. While driving, my car starts to loose power while bogging out and sound like its running on 3 cylinders. When pressing on the gas, it doenst go faster and the check engine light flickers on and off for about 10 times right before it stays on permanently. I've just changed the spark plugs but the problem keeps coming back. I hooked up the OBD II, and the code was: PO300-Random/Multiple Cylinder Misfire Detected. Now, i'm wondering if i might have to change the spark plug wires, which I havent done yet. Any recommendations? Please help.

[mp5wgn]

I replaced them with NGK's V-power... and no, i've never replaced the wires yet.

[mp5wgn]

yeah, thats what i was going to do next. do you recommend any brand in particular. the only ones i found were the magnecore 8.5mm for $77 from the www.protege5online.com, nology but they are way over $100 and some "JDM" non brand name from ebay.

[goldstar]

Other than OEM, I believe Magnecor is the only company that makes a direct replacement set for the 3rd gen, 2.0L engine.

Happy Motoring!

[mp5wgn]

cool...ill try them out. Thanks for the tips. ill let you know when i get them and if it fixes the problem.

[mp5wgn]

hey there,
I finally got the magnecor spark plug wires in and installed them...however, my car still sounds like a lawn mower and check engine is still on. So, now i am guessing I need to replace the ignition coils. Do you think that will resolve my problem or could it be something else? Please, HELP!

[ESfun]

I have a similar issue, I just posted a thread on another forum for Mazda. After looking around it may be faulty ignition coil? If you read my thread, you can see my problem. Maybe we can compare notes.

The reason why I suspect ignition coil is because sometimes, my vehicle has difficulty starting. Well, it starts, but, has difficulty catching up to the usual 1500-2000 RPM's that it should be at when starting.

[almighty4wd]

mmmm yeah, 2.5 year old thread. I doubt these fine folks will take a look. In fact, I know niether of them are on this board any more.

[MazdaDriver]

Those people may have gone away but I wish they had taken the problem with them. We have been fighting a P0300 problem for months with a 2001 Protege 2.0. The only symptom was a very rough idle when coming to a stop or decelerating, all in city driving. This lasted for about 8 to 10 seconds until reving the engine would apparently cause it to go away. Then all is fine for another 8 to 100 miles then it would do it again.

66000 miles. At the 60000 mile check up all looked very good. After the problem started the plugs, plug wires and boots were changed by the dealer, another code found at the same time had them change the mass air flow meter. But the p0300 kept coming back every 8 to 100 miles.

Then... that problem stopped happening and now we get a p0421 (cat ef. check and advise). The dealer did a cat efficiency test but could find nothing wrong. They recommended to change the o2 sensors and later the coils if the problem persists.

I just bought two universal o2 sensors at NAPA and will replace them myself. If the code comes back I will be back to this forum to search for good price suggestions for coil packs.

[ESfun]

I hope that I may be some sort of help. It may not resolve your issue, but, it may.

I had my last Po300 code cleared this past Monday. I bit-the-bullet and caved, finally took my 2002 Mazda Protege ES into the dealership. This is what they told me:

The code was caused because of 1 of 2 things. It was wither a faulty, original, EGR valve, OR, it was the platinum spark plugs that were put into my car.
The dealership told me that the platinum plugs get too hot for the Protege engines to handle and could very easily cause a "random missfire" code. The EGR was original and would explain the rough idle that I was experiencing, and the stalling. I have to say, this has been a very frustrating couple of months.

But, I took my car into 3 different michanics and they all suspencted the EGR.
One, in particular, told me that they had 2 Proteges in their shop. Both of them had the identical issue. Rough idle, slow acceleration, and stalling while idle. They replaced the EGR and all is well.
Apparently, because it is an occaisional malfunction, and is so slight, the computer doesn't know what caused the Po300 and will not kick the code for the EGR valve.
Good thing it was not too expensive to replace, but, I am stil out about $600 for the spark plugs and the EGR valve.

Well, my car now smells likenew part and I am hoping that this will solve my issue. I can completely simpathize. I will keep you posted if my rough idle happens again.

[ESfun]

Problem is back. Going to try replacing coil packs...maybe.

Gon sarn it!!!

[Kingsize]

SoSDD

Hi Guys. New to the forum, but not to the issue. I've got an '02 P5 and I'm dealing with the same issues. Mine on the other hand has not been so nice! For about a month now I've been restricted to driving short distances. Each and every time I get on a highway doing 60+mph I have a misfire/hiccup and CEL begins flashing. Thanks for the info about not using the platinum plugs....that's what I bought . So, tonight I'm headed downtown and of course, misfire, but it doesn't stop there. I lose power and the engine feels like its running on 3 cylinders or less. Guess there are a few things that need to be replaced?

Both Coils

Non-Platinum NGK OEM mazda plugs

Both O2 sensors

Plug Wires

I've also heard of P5's having issues with Cracks in the Air Intake Hose?
Also, the Shutter Valve Screws coming loose (Read a recall on '03s that can cause cylinders to flood and fault sparkplugs)

Any other suggestions???

[Beerizfood]

Try unplugging the egr valve and test drive it on the highway,it will through an egr code(s) during this test but if the egr is hanging up this will prevent its operation to eliminate it as the cause.Dont drive around all day with the electrical connector unplugged just long enough to verify.

[ESfun]

Hey again.

WOW, I am sorry to hear about your issues. They seem more advanced then mine were.

So, it has been about 2 weeks since my engine trouble. It looks like Mr. Shady McHole-the-the-wall was right, the car salesman who sold me my Protege.

All of my engine difficulties were due to the coil packs going. At least I think. The dealership also replaced the wires connecting to the coils.
When the coil packs start to go, they only mis-fire the engine cylinders sometimes. Sometimes they work fine. I guess the electrical current running through them becomes broken and random when they coil packs start breaking down.

My Silver Fox has been running fine since. Knock on wood.

Maybe it is your coil packs too? But, check your EGR first.

[diehonda]

Short of quoting each person to answer:

Check you spark plugs, if they need replacing do this, probalby needs to be done anyway.

Single cylinder misfire:
swap the ignition coils and reset the ECU. If the misfire moves with it then replace that igintion coil


Multiple cylinder misifre:
replace both iginition coils OR
get a Miata 1.8 ignition coil and 1.8 spark plug wires. Takes some wiring but only for you to bring it around to the other side of the valve cover.