so last week my car was due for an oil change, its a 2004 hyundai elantra with 64k, i decided to switch to castrol synthec instead of conventional since i use this car alot, the day after the oil change the check engine light comes on and i get this code p2626 which is the o2 sensor on the exhaust manifold, then about 2 days later just random my car looses power the engine doesnt shake or anything, i give it more gas and nothing. so i pull over put the car in neutral wait 3 seconds and then put it in drive. it takes off fine, its done this 3 times in a week. so my question is would the synthetic oil have anything to do with my car acting up. the brakes where changed the same day as the oil, could the brakes be sticking?