I need help with an 86 nissan 4X4?

It has two coils. one for the intake, and one for the exhaust spark plugs. I took it to a shop and they think that the two coils were switched, causing my truck to sputter. I just want to know if anyone knows how to tell for sure which coil goes where, because no one can give me a straight answer, and the chiltons manual doesn't tell me about it!