PhoenixRae
New member
- Joined
- Apr 10, 2024
- Messages
- 2
- Reaction score
- 0
- Points
- 1
- Genesis Model Year
- 2014
- Genesis Model Type
- 1G Genesis Coupe (2009-2016)
Firstly, I have a 2014 Genesis Coupe 3.8 Ultimate and this is my first forum post.
I bought this car around 35,000 miles and am now at ~73,000 miles. I don't know the history from before I bought it but it is all stock and I use it as my glorious daily driver. I haven't brought it to the track so I haven't put it through anything more extreme than Houston, TX highway driving (high temperatures and either high speed or agonizing traffic).
I'm looking for advice on what to try next to fix my cylinder contribution/balance problems.
Here's the story:
This started with O2 sensor error codes. I replaced both upstream O2 sensors. Problem solved... until it threw cylinder contribution codes about 100 miles later.
I replaced the spark plugs, ignition coils, and fuel injectors. Spark plugs are NGK 9723 from Rockauto, ignition coils were Densos (same brand I pulled out of there originally) and fuel injectors are some refurbished Reman GDI fuel injectors from GB remanufacturing and they look just like the original injectors.
The original problem is still there. It did well for about 180 miles after replacing the fuel injectors. Normal performance and no codes. Then, I got a contribution imbalance code and after a few more miles, another, and another. I feel little shutters while idling or traveling at very low speeds. If I reset the codes either by disconnecting the battery or using the code reader, the problem seems to go away for 20 to 100 miles. It idles normally and drives a little weak but I figure maybe that's some sort of safety mode while it waits for all the monitors to report.
But after that 20 to 100 miles, the codes and the rough idle always come back. But not the same codes every time. It always seems to be different cylinders. Cylinder 4 is a common offender and the strange part about that cylinder is that it shows the code (P0272) twice. I don't know what that suggests. An O2 sensor circuit slow response bank 2 sensor 1 (P0153) code also shows up on occasion. The problem is also progressing. More cylinders have contribution errors the longer I leave the codes uncleared. I recently had 4 out of 6 cylinders show errors and there was a very noticeable loss in acceleration capability.
I finally gave in and took it to a dealership for a diagnostic but they called me and wanted $450 (3 hrs labor) just to take the plenum off and lay eyes on the spark plugs. I've taken it off a dozen times and can do it in 10 minutes so I just wanted my car back.
I'm at a loss for what to do next. I am currently looking into the camshaft position sensors, crankshaft position sensors, mass airflow sensor, and ECM/PCM issues as possible culprits. Has anyone had similar issues? Or does anyone have advice on what I can look into next? I really love this car.
I bought this car around 35,000 miles and am now at ~73,000 miles. I don't know the history from before I bought it but it is all stock and I use it as my glorious daily driver. I haven't brought it to the track so I haven't put it through anything more extreme than Houston, TX highway driving (high temperatures and either high speed or agonizing traffic).
I'm looking for advice on what to try next to fix my cylinder contribution/balance problems.
Here's the story:
This started with O2 sensor error codes. I replaced both upstream O2 sensors. Problem solved... until it threw cylinder contribution codes about 100 miles later.
I replaced the spark plugs, ignition coils, and fuel injectors. Spark plugs are NGK 9723 from Rockauto, ignition coils were Densos (same brand I pulled out of there originally) and fuel injectors are some refurbished Reman GDI fuel injectors from GB remanufacturing and they look just like the original injectors.
The original problem is still there. It did well for about 180 miles after replacing the fuel injectors. Normal performance and no codes. Then, I got a contribution imbalance code and after a few more miles, another, and another. I feel little shutters while idling or traveling at very low speeds. If I reset the codes either by disconnecting the battery or using the code reader, the problem seems to go away for 20 to 100 miles. It idles normally and drives a little weak but I figure maybe that's some sort of safety mode while it waits for all the monitors to report.
But after that 20 to 100 miles, the codes and the rough idle always come back. But not the same codes every time. It always seems to be different cylinders. Cylinder 4 is a common offender and the strange part about that cylinder is that it shows the code (P0272) twice. I don't know what that suggests. An O2 sensor circuit slow response bank 2 sensor 1 (P0153) code also shows up on occasion. The problem is also progressing. More cylinders have contribution errors the longer I leave the codes uncleared. I recently had 4 out of 6 cylinders show errors and there was a very noticeable loss in acceleration capability.
I finally gave in and took it to a dealership for a diagnostic but they called me and wanted $450 (3 hrs labor) just to take the plenum off and lay eyes on the spark plugs. I've taken it off a dozen times and can do it in 10 minutes so I just wanted my car back.
I'm at a loss for what to do next. I am currently looking into the camshaft position sensors, crankshaft position sensors, mass airflow sensor, and ECM/PCM issues as possible culprits. Has anyone had similar issues? Or does anyone have advice on what I can look into next? I really love this car.
