hey my car has been having a miss fire at idle and under light throttle. i have pulled my codes that the car is throwing, and they are for both of my primary o2 sensors. my question is that would bad o2's cause this problem? just wondering so that i dont waste money on an o2 sensor. any help please let me know.

 

clean the codes and keep driving for a while to see what will happen.

 

I doubt an o2 can cause a misfire.. but Coils are your best bet....if I'm wrong someone please let me know

 

Could be Spark Plugs only needing to be replaced. I had a random misfire, and thought it was my O2 sensors, although never had an O2 sensor code (a maxima mechanic buddy suggested its O2 sensors) so i did O2 sensors. Even after that i still have issues. Never had a persistent code for misfire, the code came and only stayed for a few hours.

Back to OP, if you feel that car is not taking off smooth, and there is marked stuterring/hesitation when you take off, it could be coils. I am told, if its coils YOU WILL KNOW IT. If not, then like me spark plugs or O2 sensors.

 

i have some "misfire" when i start my car and after it warms up it does not do it and no light or codes

 

not saying that o2s are causing it, but remember - your primary 02s are reading the exhaust to tell the engine what fuel/air mixture to use. So if the primary 02s are bad, the engine will get bad readings and you'll run very rich or very lean. Could cause misfiring.

That said, a bad coil is the most likely culprit.

 

well i don't think it's the coil. i have replaced all of them with the upgraded ones with the silver dots. the plugs are pretty new only like 2000 miles on them. the reason i think that it's not a coil is because after you give the car some throttle and rev it up the misfire goes away, which makes me think that it would be the o2's because i know that they control the afr at idle and part throttle. i just was looking to see if someone thought the same thing that i did. thanks for the reply's i'm going to get two new primary o2's next week.

 

well i changed my primary o2 sensors yesterday and the codes are gone, but i still do get a slight mis fire but not as often or as bad as it was before i changed to o2's. i changed them because i would clear the codes and they would come back with in about an hour or two drive time, so i figured they were bad. they had over 120,000 miles with about 15 bottles of spray that had to put up with. the thing that sucks is that the misfire isn't throwing a code and i can't get it to happen when i want to so i can pull the coils off to see which one. the other thing is it's just a slight misfire not one that is as bad as a bad coil. i have had plenty of those untill i got the updated coils. i guess i'll have to wait to see if the code comes back for a misfire and maybe get lucky and it'll tell which one it is. i do get a code for my egr but i expect that because i took off my egr guide tube and the sensor that was in it is just hanging, but i'll eventually put it in the block off plate that i made for the egr.
i'm sorry to keep rambling i'm just hoping someone might have a suggestion for this problem as it's bugging me. thanks

 

Did you ever get your problem figured out? I am seeing something very similar.

A while back (6 months ago) my SES light would go off and on. When I got the codes read, it showed O2 sensor(s) were bad. The car was running fine, so I never did anything with it.

Lately it is running rough in idle (drive and reverse), but runs fine going down the road, this was an intermittent problem.

I changed the plugs and actually made the problem worse. Now, it is happening all the time. I got the codes read again, and it showed mis-fire on Cylinder 2. I moved the plug,spring and coil from cylinder two, had the codes read again and it showed multiple mis-fires. I thought I was on the right track and was hoping I could replace a coil and call it good. But wanted to make sure because I had the plugs out of both cylinders checking for spark. So I had them clear the codes and was hoping for a cylinder four mis-fire this time. But, I had the codes read and it is still cylinder two.

Doesn't make sense to me.

Any ideas?