hello everyone, y 2013 auto has some gearbox issues. a few weeks ago a warning light came on and it wouldn't shift into 5th or 6th gears without revving out to max. the dealer said it just needed oil and that he would fix it. a week later and the car was returned. after a day or 2 the gearbox started doing the same again. plus low engine oil warning light came on also. dealer basically told me its my problem(only bought the car 3 months ago).
took the car to an independent garage and they inspected it. the air filter was years old and the oil filter was falling apart inside so the car has not had the service that was promised. this brings into question everything they told me they had fixed.
the car now when driving about 20/30 mph will seem to be slightly accelerating/decelerating slightly as if i was ever so slightly feathering the accelerator and if i accelerate too quickly(more than half throttle) will not change up through the gears. if i ease off the accelerator it sometimes will change up but this is very dangerous. what would be causing it to not shift and to flutter at lower speeds. any help or advice is welcome please