p0090/p0300

[RJHTUNER]

I got a 2003 mazda protege lx thats been acting up at times and here are the symptoms rough running at times, hard to start at times, hesitates while driving sometimes but at idle in park it doesn't hesitate. but like I said it doesn't act up all the time! I have CEL CODES P0090/ P0300 IF ANYONE HAS HAD THIS ISSUE WITH THESE CODES PLEASE HELP ME WITH SOME INFO! Thanks!!

[irishkev90]

This was posted in the wrong section, but I'm sure someone will move it soon and goldstar should be able to help you. He has a third genertation (BJ) Protege as well.

[RJHTUNER]

Thanks for letting me know! I didn't notice until u told me lol

[irishkev90]

It's okay. Happens a lot with new members.

Also, I did a quick Google search and the P0090 code seems to point to low fuel pressure and the P0300 code is for a random misfire. I'd guess that if you can solve the P0090 code then the other will go away. I'd check/replace the fuel pump, fuel filter, fuel pressure regulator and even injectors.

[EGTeric93]

^ he is dead on haven't looked up the 90 code but 300 is random misfire for sure..

Chances are its the fuel filter fpr or pump.. Injector issue will typically throw a single cyl misfire code as well as a p1xxx code

Start with the filter and clear the codes if it comes back and the car has never stalled it's a safe bet it's the fpr due to hard starting.. If it only misses and stumbles after its been running for a while the fuel pump is getting hot and not working right

[EGTeric93]

Also wouldn't hurt to just do a full tune up if the milage is up there and it hasn't been done..

As well as check vac lines for fPr and intake as low vac could effect the fpr as well as cause misfire

[tweety2300]

Coil packs are going, dura last from autozone has been going without issues on mine for 2 years. If its a plug or plug wire it will give a code for that specific cylinder. When a coil pack goes it will give the p0300 random as in its happening in more than one cylinder. If you keep driving it with the p0300 it will dump fuel into Pre cat and destroy it which you will get p0421.

Clear the p0090 if it comes back go to Mazda and get a new gas cap, do not get one from a parts store, they do not like them. Actually before that make sure the gas cap is tight. 3rd gen protégés have a non serviceable filter built into the fuel pump.

Sorry for long post just trying to give a detailed response

[RJHTUNER]

I recently replaced the coil packs and cleared the codes and its still doing the same thing..

[Turpro]

Didn't the newer pros have a problem with the intake am if old gaskets? I know my mpv threw a code for misfire and turned out to be a bad intake mani gasket

[EGTeric93]

Def always use dlr gas caps on all cars aftermarket sucks... That's the only advice I would personally take from that post..

A bad gas cap will throw a p0440 or some sort of evap code.. Or tank pressure sensor..

If the fpr is still vac driven turpro is right.. You prolly have a vac leak allowing unmetered air..

AUTOZONE and especially DURALAST is garbage.. DURALAST is just a rebox of the cheapest part AZ can find for the "house" brand go with BWD or Standard.. They will long outlast anything DURALAST and most part stores will price match

[tweety2300]

Because you know I own a protege and have dealt with none of mentioned issues.

Either way if you still have the p0300 change Plugs and wires. If its still there the egr valve can cause the p0300 on some rare circumstances. Check out mazdas247.com lots of 3rd gen support over there

[EGTeric93]

Never said u haven't.. But your going in the wrong direction.. The p0090 code has to be fixed first... It has priority and will cause a 300 code so changing the plugs and coil packs although they may be needed will not solve the problem..

Would I be wrong in assuming you have no professional training and that u are strictly a DIY? Cuz it's either that or your a rep for AZ..


To the op..

Get yourself a can of starting fluid and spray it all around the intake and vac lines and listen for a raise in idle.. Or go the technical way and hook up a vac guage.. Make sure you rule that out as well as test the fpr b4 throwing any more ignition parts at it.. The p0090 needs to be fixes first

[EGTeric93]

Never said u haven't.. But your going in the wrong direction.. The p0090 code has to be fixed first... It has priority and will cause a 300 code so changing the plugs and coil packs although they may be needed will not solve the problem..

Would I be wrong in assuming you have no professional training and that u are strictly a DIY? Cuz it's either that or your a rep for AZ..


To the op..

Get yourself a can of starting fluid and spray it all around the intake and vac lines and listen for a raise in idle.. Or go the technical way and hook up a vac guage.. Make sure you rule that out as well as test the fpr b4 throwing any more ignition parts at it.. The p0090 needs to be fixes first

[EGTeric93]

Egr is a possibility as well he is right there but that causing your issues would be due to guess what believe it or not a clog in vac ports.. Which would elaffect a vac driven fpr. Bringing u back to fix the 90 code first

[tweety2300]

Egr valve and coil pack failure is very common in the 3rd gens and considering a precat through Mazda is $1,000 last I checked and its very sensitive. But I'm not going to sit here and argue with someone that has more general knowledge than me. I'm just saying the very common fixes for these issues since they pop up all the time