Good Evening-
I have the inline 4.0l, automatic with 129k on this vehicle that was running fine before it sat for a month. Now on startup it threw a po302 error , runs like garbage on acceleration , bogging down and sputtering, as well i have a po135 and a po158. Is it possible that its only a spark plug issue, causing un-burned fuel to trigger the high voltage on bank 2 sensor two even though the miss is on bank 1 ? I ordered the coil pack as a precaution and will be doing the plugs first. I clear the codes and they all return on next startup and test drive.
Thank You for any assistance!
A quick test would be to try swapping the #2 coil with another cylinder and see if the misfire travels with the coil. Also check to see if that spark plug is fouled up.
@ ChuckTobias
Thank You for a speedy response, unfortunately the 4.0l has a "coil rail" pack that doesn't allow for that. Something similar to: https://www.summitracing.com/parts/msd-82738/make/jeep/model/wrangler/year/2004
Bummer. I'm more familiar with the older 4.0 engines that have a distributor. It would still be interesting to check the plug on that cylinder and see if it's showing signs of distress.
po302 error
Please see the FAQ under misfire.
po135
P-zero 135, not po135
This is failed sensor heater circuit. If the heater doesn't work, then neither will the sensor. If the sensor doesn't work, the engine won't run right.
Check the wiring and replace if necessary.
You can ignore sensor 2 for now. It doesn't affect the engine.
https://www.youtube.com/watch?v=svDzJMEnVD0
@MountainManJoe
Thank you kindly!