My car is experienceing a 1 2 shift problem. The problem is sometimes it shifst into 2nd and smoetimes it won"t. sometimes when it shifts it neutrals out and somes times it works just fine and sometimes won"t go in at all filter and fluid changed any one have an answer. Ps check engine light on in car.

The Light is telling you something is wrong, Take to a shop to read the code(s), or buy a code reader for less than $40.
A $20 Service Manual, will show how to read the engine light flashes without a reader.