Been noticing a slight misfire at part throttle over the last month.
It has now got really bad.. so bad that I noticed it gets much worse when the car goes into closed loop i.e. when the O2 sensor starts providing feedback after the car is warm. (edit correction: it happens all the time) - Get to a traffic light and it will stumble and fall below normal idle, catch itself.. any type of throttle tip in is a nightmare that causes a serious miss. Not a pop and crack type of misfire, more like a low rumbling and stumbling type of misfire. its way worse in closed loop mode but the other day at idle it was very rough and I had just started it first time that week.
I've been having a P0302 code for a while now and it used to come on every few days, now its instant.
I have checked the cylinder and it looks good, but for some reason the plug on #2, outside rim and ground prong were very rusty (edit: I was wrong, all plugs are equally rusted). I replaced the plugs, all seemed good, until the car warmed up and the dreaded mis came back and it was back to square 1. Cylinder 1 plug was also a bit rusty.. but all other plugs looked normal.
I'm going to log a lot of parameters tonight and try to look for anomalies that would point to an issue.
My first thought was a vacuum leak, but it fine until she gets warm - my LT trims are 1.08 on both banks though, telling me it could be a leak. the ST trims are spot on at idle.
Here is where i'm going
1. MAF? cleaned it and it looks good, but that doesn't mean anything - how can I log this and confirm its OK?
2. O2 sensor? i'm not getting a code but the gradual nature of the failure tell me this could be the cause especially since it really pukes when I get on the throttle.
3. Bad injector on cylinder 2? I have the ford racing 47lbs injectors but after 3yrs on E85, maybe that one gave up?
4. Bad coil? I don't think so, I swapped coils and the misfire stayed at cylinder 2.
I inspected the cylinder it seems OK (edit: I only looked at the lack of oily plug), runs clean, and no smoke at all from the car.
help appreciated, i'll post up the logs here.
Thanks!!
It has now got really bad.. so bad that I noticed it gets much worse when the car goes into closed loop i.e. when the O2 sensor starts providing feedback after the car is warm. (edit correction: it happens all the time) - Get to a traffic light and it will stumble and fall below normal idle, catch itself.. any type of throttle tip in is a nightmare that causes a serious miss. Not a pop and crack type of misfire, more like a low rumbling and stumbling type of misfire. its way worse in closed loop mode but the other day at idle it was very rough and I had just started it first time that week.
I've been having a P0302 code for a while now and it used to come on every few days, now its instant.
I have checked the cylinder and it looks good, but for some reason the plug on #2, outside rim and ground prong were very rusty (edit: I was wrong, all plugs are equally rusted). I replaced the plugs, all seemed good, until the car warmed up and the dreaded mis came back and it was back to square 1. Cylinder 1 plug was also a bit rusty.. but all other plugs looked normal.
I'm going to log a lot of parameters tonight and try to look for anomalies that would point to an issue.
My first thought was a vacuum leak, but it fine until she gets warm - my LT trims are 1.08 on both banks though, telling me it could be a leak. the ST trims are spot on at idle.
Here is where i'm going
1. MAF? cleaned it and it looks good, but that doesn't mean anything - how can I log this and confirm its OK?
2. O2 sensor? i'm not getting a code but the gradual nature of the failure tell me this could be the cause especially since it really pukes when I get on the throttle.
3. Bad injector on cylinder 2? I have the ford racing 47lbs injectors but after 3yrs on E85, maybe that one gave up?
4. Bad coil? I don't think so, I swapped coils and the misfire stayed at cylinder 2.
I inspected the cylinder it seems OK (edit: I only looked at the lack of oily plug), runs clean, and no smoke at all from the car.
help appreciated, i'll post up the logs here.
Thanks!!