2012 Citadel 5.7 AWD misfire on cyl 3
#1
2012 Citadel 5.7 AWD misfire on cyl 3
117k miles, new transmission about 3 months back. Still love the ride, the engine has developed an issue that triggers the CEL. Mechanic replaced the spark plugs and replaced the valve cover gaskets after checking for broken springs on the heads, still getting a CEL and same code for cyl 3 misfire. About 2 weeks ago, replaced the coil pack for cyl 3 due to same CEL and code.
Lately it has had some electrical quirks - radio not keeping the stations, seat presets not keeping the settings, pop ignition and use key, FCW warning comes on frequently, lift gate not going up all the way sometimes - can an issue with electrical cause this kind of issue (misfire) on these cars?
From reading through other's working through similar issues on this forum, these are the things that sound like may be worth the small investment of time for the mechanic to check before concluding it is a mechanical issue (likely lifters or cam from the common themes across the forum):
replace spark plug wires (at least on cyl 3)
Crank shaft position sensor
unplug upstream oxygen sensor and see if the car runs better or worse
exhaust valve/ valve seating
I did some searching and for what it would take to (worst case) rebuild from the heads up shop estimate of $5700, it might be more efficient to get a crate motor instead - any suggested (keeping it stock) ways to look into that? Buying just the needed replacement parts seems like it is half way or more to a crate engine (long block with intake, etc fully assembled)...
Lately it has had some electrical quirks - radio not keeping the stations, seat presets not keeping the settings, pop ignition and use key, FCW warning comes on frequently, lift gate not going up all the way sometimes - can an issue with electrical cause this kind of issue (misfire) on these cars?
From reading through other's working through similar issues on this forum, these are the things that sound like may be worth the small investment of time for the mechanic to check before concluding it is a mechanical issue (likely lifters or cam from the common themes across the forum):
replace spark plug wires (at least on cyl 3)
Crank shaft position sensor
unplug upstream oxygen sensor and see if the car runs better or worse
exhaust valve/ valve seating
I did some searching and for what it would take to (worst case) rebuild from the heads up shop estimate of $5700, it might be more efficient to get a crate motor instead - any suggested (keeping it stock) ways to look into that? Buying just the needed replacement parts seems like it is half way or more to a crate engine (long block with intake, etc fully assembled)...
#2
With all the different electrical quirks you describe, I would suspect an electrical flow interruption including a poor or loose ground wire. For the cyl 3 misfire, even after the spark plug, spark plug wire and coil were replaced, the coil still gets its electrical pulse from the computer. Noting that the trans was recently replaced, I would look into a possible snapped or loose hot or ground wire that may have been damaged during that service. - Just a thought.
#4