Hyundai Repair: check engine light, transmission control module tcm, hyundai computers

Question
iam having the same problem as one of the other people,when i run one errand my car is fine if i run a couple errands the car starts to run bad i feel like iam in N my rpm go up to 3-4 and then all of a sudden the car clicks into gear and my check engine light comes on i was just told it is my trans modular control,how true is this?and what is the round about cost for this part
believe me i love my car and have had it for 6yrs and have no other problems with it

Answer
It's doubtful the problem is in your transmission control module (TCM).  Hyundai computers have proven to be quite reliable.  

It's possible the repair will be simple or complicated.  To help determine the issue, I'll need you to have your engine and transmission diagnostic trouble codes read.  AutoZone and AAMCO have advertised they'll do this for free.  I'll be interested in the code numbers themselves, not the definitions provided by the code reader or the operator.