P0300

[Laramie]

I'm pulling a P0300 on my 2003.5 MazdaSpeed Protege. Everything is stock. I was running lean because of a faulty WGA, but I replaced it along with my vacuum lines and haven't seen a lean CEL since.

The problem I'm experiencing is that every couple of days the car suddenly bogs down and has no power like its only running on 1 or 2 cylinders. The idle goes down to 200-400 so I have to give it gas to keep it from stalling. Usually about 30 seconds later the engine comes back to life and everything runs fine again for a couple of days.

Sometimes the CEL even goes away on its own. I've cleaned the MAF sensor and EGR valve in the past two months and the EGR seemed fine to begin with.

Any ideas?

Thanks guys,

Laramie

 

[Metallic36]

That CEL is for the Multiple Cylinder Misfire.. not that good. Do a search about it, you'll find out a lot.

 

[lowpro35]

That CEL is for the Multiple Cylinder Misfire.. not that good. Do a search about it, you'll find out a lot.

agreed, misfires can be cause by a lot of things. bad maf, bad plugs, bad O2s, bad cats, bad fuel, bad fuel pump, clogged injectors, it's a long list.

 

[StealthWyvern]

multi missfire is generaly caused by bad plugs, bad wires or bad coil packs... its more then likely the wires or packs imo.

 

[lowpro35]

multi missfire is generaly caused by bad plugs, bad wires or bad coil packs... its more then likely the wires or packs imo.

yep, it's either fuel or ignition, or something that helps make those happen.

 

[Kooldino]

multi missfire is generaly caused by bad plugs, bad wires or bad coil packs... its more then likely the wires or packs imo.

+1

 

[Laramie]

I should have indicated that I have extensively researched the problem on this forum.

Most people have this CEL in conjunction with another, but the random misfire is the only code I ever pull. I've replaced the spark plug wires about 20k miles ago, but haven't done the coil packs. Is replacing the coils a good first step?

I'll pick them up this weekend and swap them out.

 

[Metallic36]

Yes. That will solve some of the strangest problems sometimes.. you have someone post a HUGE thread of issues, and it turns out to be the coils. :dodgy:

Is replacing the coils a good first step?

I'll pick them up this weekend and swap them out.

 

[Jboost]

So what's the word my car is doing the same thing I cleaned my egr and replaced the spark plugs and the car is still doing it. If this works for you I will over night my self a new set of coils

 

[Jboost]

So i found a small crack in my cold pipe i will be patching this asap but what are the chances that this is making me throw the p0300 code. I'm guessing slim but still wanted to check with everyone and whats the point of starting a new thread when there is one on the same thing already.


p.s. I ordered up new coil packs should have them wednesday we will see what that does.

 

[Laramie]

I haven't had a chance to install new coil packs yet, but I was reading about the VICS/VCTS problem and I'm wondering if that is my issue as well. I notice the VCTS "rattle" when my car is warming up and sure enough it always stops after the car is fully warmed up. However, it only started making the sound while cool during the last 5k miles.

Is it possible that my bogging is caused when a VICS screw falls into the engine? My car doesn't fall under the recal VIN numbers, but the symptoms sound awfully similar.

 

[323]

subbin. got the same issue. jus replaced plugs and wires and soon the coils to see if it goes away

 

[Laramie]

OK. It took a while to find the time, but I've replaced my ignition coils. While I was at it I went ahead and put in a new valve cover gasket as well. The old gasket was slowly leaking.

It has been 2 days since swapping the coils and I haven't had a CEL or any malfunctioning. I'll give you guys another update in about a week to let you know if I have continued success.

 

[323]

did u notice an improvement when idling?

 

[Laramie]

I didn't notice any improvement when idling, but it was already pretty steady to begin with. I haven't had the issue where the engine bogs while I'm driving however. Before the swap, the engine would typically bog once or twice a day for 10-60 seconds. Lately it was bogging down for up to 3-4 minutes so I think the coils fixed it. Only time will tell.

 

[Laramie]

Still Working Great

Just wanted to let everyone know that the car has been running great for a few weeks now after replacing the coils.

If you're getting odd symptons and random misfires, don't overlook swapping the coils. It's cheap and easy.

 

[323]

did u get oem coils or did ya get them from a local autopart store?

 

[GAME100]

ok guys i got the p0303 code about 2 weeks ago. i replaced the plugs with iridium ones and everything was alright for about a week but one day i got the code again. symptoms are hesitation, bogging down in low rpm, etc. i also noticed the spark plug wire in cylinder 3 popped off. i pushed it back in but it popped off again after i drove it. right now im gonna change the plugs to the stock ones. but what do u guys think, bad wire, coil? or something worse...internal problems in the cylinder??? btw my car is stock except for boost controller set @ 8psi and the forge bov.

 

[orng1]

I'd replace both the coil and wire to see if it fixes it. Its not expensive and due if your having issues. Take the opportunity to replace the plugs to see if that cylinder is doing anything odd.

 

[GAME100]

yea thats wat i was thinking. where can i get the coil??