If it turns out to be a factory computer then check it for fault codes.
Theres a guide somewhere on here, just find it using the search.
If its a link you may need to take it in or depending on the verions someone on here may be able to plug it into a laptop and have a look for you.
Thats my 2c's but someone else might be able to suggest something else based on symptons.
Either way its not a bad idea to spend 10 minutes and pull the ECU out to see what its running.