I have a 05 Rev Up, and I had a P0340 code along with louder exhaust sound coming from the passenger side of the engine. I replaced the camshaft sensor with a OEM one and the code is gone but the sound from the engine is still present. Some background info: I probably put about 2000 miles on my G in 2018. I had not changed the oil all year and a friend said the P0340 code was the result of old oil. I changed the oil in October, but the code was still there. I drove it very little and the louder engine sound became present. I changed out the camshaft sensor in December and ran seafoam through the vacuum tube to see if there was an exhaust leak. Smoke only came out of the end of the muffler. So the car sounds pretty bad, and it seems like there is a loss of power. Any help is appreciated.

Probably an exhaust leak.