98 5.2 Dakota jerks hard at highway speeds
#31
A high speed (indicated) miss could be a lazy O2 sensor or a lazy crank position sensor.
The computer uses O2 timings to measure for a miss by somehow figuring out which exhaust pulse is which cylinder (I didn't think the PCM was fast enough to do that, but I digress). A lazy O2 sensor at high speed can make the PCM think there's a miss.
A lazy crank sensor will actually cause a miss, as it will throw off the fuel sync and spark timing. This is then picked up by the O2 and reported.
The computer uses O2 timings to measure for a miss by somehow figuring out which exhaust pulse is which cylinder (I didn't think the PCM was fast enough to do that, but I digress). A lazy O2 sensor at high speed can make the PCM think there's a miss.
A lazy crank sensor will actually cause a miss, as it will throw off the fuel sync and spark timing. This is then picked up by the O2 and reported.
#32
A high speed (indicated) miss could be a lazy O2 sensor or a lazy crank position sensor.
The computer uses O2 timings to measure for a miss by somehow figuring out which exhaust pulse is which cylinder (I didn't think the PCM was fast enough to do that, but I digress). A lazy O2 sensor at high speed can make the PCM think there's a miss.
A lazy crank sensor will actually cause a miss, as it will throw off the fuel sync and spark timing. This is then picked up by the O2 and reported.
The computer uses O2 timings to measure for a miss by somehow figuring out which exhaust pulse is which cylinder (I didn't think the PCM was fast enough to do that, but I digress). A lazy O2 sensor at high speed can make the PCM think there's a miss.
A lazy crank sensor will actually cause a miss, as it will throw off the fuel sync and spark timing. This is then picked up by the O2 and reported.
Apart from that, last weekend i unplugged the o2 sensor, i felt sluggish while driving and guess what, it did it again!!! So, i dont think the o2 sensor is causing this.
What i did was to put together a table with the misfire counters that i have been getting when driving at high speed, this is what i came up with:
Interesting things
- Always its at high speed
- The jerk thing doesn't happen at the same time as when the solus is displaying misfires but this may be due to the Solus not really presenting the misfire data in real time
- Its almost always the same cylinders
- Taking a closer look, all cylinders missing present about the same number of misfires, is not like one has considerably more than any other
Another thing i did was to check the firing order:
If I sort the table by firing order (instead as by cylinder number) this is what i get:
Interesting fact
- Its always like one fires, next one fails, one fires, next one fails
If you have any ideas, let me know
My next step will be to swap the injectors from the cylinders that are miss firing to the ones that are not and vice versa
#35
Wasn't there a write up on spark plug wire routing to keep them from arching off each other or something like that?? It sounds like a lean surge, but if it's missing it's gonna show it's running Rich because of the unburned mixture. What temp coolant does the ecm show?? And what temp air does the ait show?? If you can get those readings on your scanner.
#36
Like 7 or 8 months, that is the first thing i replaced when the issue started
Wasn't there a write up on spark plug wire routing to keep them from arching off each other or something like that?? It sounds like a lean surge, but if it's missing it's gonna show it's running Rich because of the unburned mixture. What temp coolant does the ecm show?? And what temp air does the ait show?? If you can get those readings on your scanner.
Here is a snipe of the Solus with some of the important PIDs, the blue line shows when the issue was present:
#38
#40
So after reading the whole thread did you ever get that problem figured out?
I'm basically in the exact same boat with my 98 5.2l dakota and its been driving me nuts. Pretty much replaced every sensor and tuned everything up that I could think of and its still having this exact issue. I'm waiting on the new aluminum plenum plate from hughes to see if by some chance the factory one is causing an oil leak thereby causing it to go rich and cut fuel way to much in closed loop hwy driving.
I'm basically in the exact same boat with my 98 5.2l dakota and its been driving me nuts. Pretty much replaced every sensor and tuned everything up that I could think of and its still having this exact issue. I'm waiting on the new aluminum plenum plate from hughes to see if by some chance the factory one is causing an oil leak thereby causing it to go rich and cut fuel way to much in closed loop hwy driving.