I recently purchased a used 2011 Regal. The car ran great for a week. I had decided to do an oil change and an inspection performed to just make sure the seller wasnt hiding anything.

The inspection came back clear, and it included a test drive by the inspector. After the oil change, there was a very noticeable increase in the sensitivity of the gas pedal and the car would jump (accelerate) randomly when slowing down. The day after the oil change, I had a random engine cut off while turning onto a parking lot. The engine was not shaky or running rough at this time and I didnt know the engine was dead initially. The car would start back up instantly, but would die when put in drive. After trying a couple times, the car started and ran perfectly fine straight home.

I used my code reader and came up with p0016 and p0011. I spent a ridiculous amount of time researching this problem and was about to replace the intake and exhaust solenoids myself, but figured this should be left for a proper mechanic. In case the problem was a bad wire or something I was overlooking.

The mechanic told me the problem was the solenoids and would call me once he had finished. Three days later I called him as those take 10 minutes to replace and 3 days is goofy. He told me he replaced the solenoids and replaced a bunch of air filters (I did not authorize this work). And he believed the problem to be the timing chain being a jumped tooth.

He did not check the wiring to the solenoids, or test the previous solenoids to verify they were bad. Just believed the new rough idle was indicative of a bad timing chain.

Given that I was able to restart the car and drive home without a problem, and no rough idle, I felt like it was electrical in nature. I bit the bullet and had a dealership look at it. I spent a lot of time trying to figure out what could cause the engine to die in the way it did and given the codes (p0011, p0016) I figured it's probably the camshaft or crankshaft sensors. I took a camshaft sensor to the dealership and asked him to replace it if he cant find a cause.

The tech at the dealership tested the new solenoids and found they were stuck open. He tested known good solenoids and found those were stuck open as well. He tested the wires from the solenoids to the ECU and did not find anything wrong with them.

He put the camshaft sensor in that I provided and the car ran perfect after. They did a test drive around their block and it seemed fine. After taking possession of the car, I took it for a test drive and after about 30 minutes, the CEL came on and the error code it p0011. The car did not have a rough idle. But was mildly jumpy at low speeds and while decelerating.

The car currently has a rough idle when started and I suspect the solenoid is stuck open. My gut tells me this is a grounding or chaffed wire issue, but the dealership is recommending I replace the VVT Actuator, which means an entire timing system replacement.

Of note, the headlamp is half full of water from a bad seal and lots of rainy weather. I'm going to remove the headlight tomorrow and dry it out and reseal. Not sure if a water logged ballast can cause a weird short, or water splashing around under the hood?

Is there anyone on here with insight into something like this? Is there a ground-point that I could check or a test I can do on my own?