Engine codes

I have a 96 Plymouth Voyager 57,000 miles. The van started stumbling about two days ago randomly and then today it acted as if it was going to run out of fuel.(It had plenty) Almost not making it up a small hill. Thats when the "Service Engine Soon" light came on. Here are the codes I got from it. 12, and 43. The 12 is a battery disconect code. But the 43 said it was either a cylinder misfire or a problem in power module to logic module interface.(Whatever that means) Where do I start to look for the problem?