Who can figure this one out???

[zacharygerdes]

So yesterday i get the milly out and when im driving the check engine light starts blinking (i know thats not a good thing). so i pull over and shut the car off and it starts missing. So i drive the car home and let it sit over night the next day it works perfect. I bring the car to my uncle who is a mecanich and he pulls the code and it is a misfire on cylinder 4. He waits a day and drives it and it runs fine. So we decided to see how long it was before the light started blinking again. I drove it for about 2 months with no problems and now it started again. So here is the history.... the check engine light has been on for about 20K (catylatic converter warm up issue) i talked to the mazda mechanics and they said this shouldnt casue any problems just an emsions thing. So now i get codes P-0421 (CC warm up issue, not to worried about this one) and P-0304 misfire on cylender 4. So my question is what should i replace first. I dont really want to replace everything if i dont have to (my uncle is great but doesnt work for free ) Im guesing it is a coil pack on cylender 4, or plug. Could anything else be causing this issue. The wierd thing is it will work for a while (2 months) and then misfire, so could it be a plug or wires?
Hope you guys can help (you haved out big time in the past)
Thanks in advance

[Matt64341]

So yesterday i get the milly out and when im driving the check engine light starts blinking (i know thats not a good thing). so i pull over and shut the car off and it starts missing. So i drive the car home and let it sit over night the next day it works perfect. I bring the car to my uncle who is a mecanich and he pulls the code and it is a misfire on cylinder 4. He waits a day and drives it and it runs fine. So we decided to see how long it was before the light started blinking again. I drove it for about 2 months with no problems and now it started again. So here is the history.... the check engine light has been on for about 20K (catylatic converter warm up issue) i talked to the mazda mechanics and they said this shouldnt casue any problems just an emsions thing. So now i get codes P-0421 (CC warm up issue, not to worried about this one) and P-0304 misfire on cylender 4. So my question is what should i replace first. I dont really want to replace everything if i dont have to (my uncle is great but doesnt work for free ) Im guesing it is a coil pack on cylender 4, or plug. Could anything else be causing this issue. The wierd thing is it will work for a while (2 months) and then misfire, so could it be a plug or wires?
Hope you guys can help (you haved out big time in the past)
Thanks in advance[/b]

I am assuming you have the 2.3, so if you don't this info doesn't apply. Take the coilpack from cylinder 4 and switch it with cylinder 2 or 6 (left or right). Then clear the code and wait for it to return. When it does, check the code. If you get P0302 (or P0306 if you did cylinder 6), then the ignition coil is bad and it should be replaced. If it comes back as a P0304 then you may have a bad plug, a bad injector, or one of a couple of very unlikely causes. To me it sounds like a coil though.

[zacharygerdes]

I am assuming you have the 2.3, so if you don't this info doesn't apply. Take the coilpack from cylinder 4 and switch it with cylinder 2 or 6 (left or right). Then clear the code and wait for it to return. When it does, check the code. If you get P0302 (or P0306 if you did cylinder 6), then the ignition coil is bad and it should be replaced. If it comes back as a P0304 then you may have a bad plug, a bad injector, or one of a couple of very unlikely causes. To me it sounds like a coil though.[/b]

Thanks Matt,
Yeah it is an S. Ill give that a try tom. Any idea were to get a coil pack for cheap? Im guessing ebay, I think they are like 80 bucks.

[Matt64341]

Thanks Matt,
Yeah it is an S. Ill give that a try tom. Any idea were to get a coil pack for cheap? Im guessing ebay, I think they are like 80 bucks.[/b]

eBay, junkyard, or a part out - but I don't think anyone on here is parting out right now. You can usually get them used from $30-40

[gramnarine70@hotmail.com]

eBay, junkyard, or a part out - but I don't think anyone on here is parting out right now. You can usually get them used from $30-40[/b]

Hey,

I have the exact same problem with the misfire in cylinder four in my 99 s model. Im looking to replace the coil, just shopping around for it right now. I just hope the other coils are fine and this doesnt get too costly :S.

[guitarzan134@hotmail.com]

i had a VERY similar problem with my '02 S. My car ran as though it were misfiring. we replaced all the parts that the codes called for, but the misfire was still there. I then took the car to Mazda Tech, 1000 bucks later. it ended up being broken T's in the intake vacuum line, another $350 for p&l. car runs GREAT now.

[Matt64341]

Hey,

I have the exact same problem with the misfire in cylinder four in my 99 s model. Im looking to replace the coil, just shopping around for it right now. I just hope the other coils are fine and this doesnt get too costly :S.[/b]

Do the troubleshooting steps above to make sure it is the coil before you assume and buy one.

i had a VERY similar problem with my '02 S. My car ran as though it were misfiring. we replaced all the parts that the codes called for, but the misfire was still there. I then took the car to Mazda Tech, 1000 bucks later. it ended up being broken T's in the intake vacuum line, another $350 for p&l. car runs GREAT now.[/b]

Throwing parts at the car will usually end up with a lot of wasted money. Most of that $350 is labor, the vac lines and T's are cheap parts.

[Goliat6288]

Matt you forgot to mention that they were probably plastic T's which will break somewhere in the future while if done by themselves they would have had brass T's and a long gone problem.

[Matt64341]

Matt you forgot to mention that they were probably plastic T's which will break somewhere in the future while if done by themselves they would have had brass T's and a long gone problem.[/b]

It is true, I expect that the brass T's and silicone hoses I have on mine will outlast rest of the engine. It is not unheard of for Plastic T's to break after just a few years, and the rubber lines dry out and crack.