random misfire

[JDMazdaFamilia]

I have a random misfire cel and my car runs like crap. It runs very choppy and power seems to be not there. On my way to work it started doing it and I can't figure it out. The plugs are fine. How do I test the coils to see if they're good? What else could it be?

 

[Cmezz331]

Vac/boost leak

 

[JDMazdaFamilia]

Is it normal that with a vac leak it happens over a moderate amount of time? I have a small vac leak but it's been running fine like that for 3k miles.

 

[josh182]

Mine just started being extremely choppy too, only at full boost though. almost as if its cutting power, finally got a check engine for it after a few days, its saying air/fuel ratio, so maybe it could be that for you?

 

[RicoP5]

Mayb the o2 sensor?

 

[JDMazdaFamilia]

I have an o2 sensor code too.. How would I go about checking if the o2 is bad? I hate to replace parts and then to conclude that wasn't the problem.

 

[JDMazdaFamilia]

That day it started doing it I could smell a burnt sensation too. Idk if that means it was running lean..

 

[jim9]

How many miles on your car? Misfire could be many things, injectors, coil, spark plugs, maybe even wires/ecu. I don't think vac leak is the issue but worth the check. Also what are the codes you're getting?

 

[JDMazdaFamilia]

I've got 50k on the swap. Is there anyway of sourcing the problem by strategies to eliminate others? Plugs appear to be fine. The guy at shucks wouldn't let me look at the obd scanner but it was a random misfire code and downstream o2 code

 

[RicoP5]

I've got 50k on the swap. Is there anyway of sourcing the problem by strategies to eliminate others? Plugs appear to be fine. The guy at shucks wouldn't let me look at the obd scanner but it was a random misfire code and downstream o2 code

Take the o2 out clean it with brake cleaner then see what happens..
If not

http://item.mobileweb.ebay.com/viewitem;PdsSession=fe4907321380a47a19621002ffee927f?itemId=380448114964&cmd=VIDESC

 

[jim9]

Yep, then try the o2 first but imo i dont think its the cause as I've had both those codes before. I've used autozone/oreilly o2 with no issue what so ever. Oh also, just buy an obd2 reader its better off to know the exact code/#.

 

[JDMazdaFamilia]

I have a non fouler should i take it off or leave it on? Yeah I really do need an obd scanner. Rico that link didn't work for me..

 

[JDMazdaFamilia]

I was thinking of ordering the app for my iPhone. Seems pretty legit

 

[JDMazdaFamilia]

Still haven't figured it out.

I have code p0300- random/multiple misfire
&
Potential code- p0140- downstream o2

 

[CHIQLES]

torque program for android lets you see graph for o2 signal spikes mean 02 is dead suttle ups and downs with flat tops on profile indicate o2 is reading correctly

 

[CHIQLES]

missfires under boost when it happend to me turned out to be coils replaced them 3 times before i got a good set..

 

[bwlknsn91]

That day it started doing it I could smell a burnt sensation too. Idk if that means it was running lean..

Just noticed the same thing on my car. After driving it mild to moderately hard, I'll notice a burnt smell near the engine bay when I get out of my car. And I'm also having codes about a possible bad o2 sensor on the exhaust manifold. Really leaning towards a bad o2 sensor, but for safe measure I'm gonna smoke it and double check there are no leaks.

 

[CHIQLES]

well if your smelling burnt maybe its your cat you have to wonder why the 02 died

 

[bwlknsn91]

well if your smelling burnt maybe its your cat you have to wonder why the 02 died

I'm not sure if this is directed towards me or not, but how would the cat effect the first o2 sensor? I'm just thinking it could be the o2 sense I'm havin idle issues and wasn't sure of it were all related somehow.

 

[CHIQLES]

im just saying the smell but if you dont fix the o2 the cat will die..