2000 Pontiac Montana Hesitation or surging

When the RPM gauge goes up and down, is the transmission slipping or does it only happen at an idle?

It doesn't happen in idle at all it's while I'm driving

Does it feel like the trans is slipping? Have you checked to make sure the catalytic converter isn't plugged? Have you checked fuel pump pressure?

It doesn't feel like the transmission when it sometimes the lite will turn on or low oil pressure light will come on

When you say light, are you referring to the check engine light? As far s the oil light, it may come on if the RPM's get really low.

If it is the check engine light, have you had the computer scanned for trouble codes?

The check engine doesn't come the battery light does or the low oil pressure sometimes

Okay, those come on if the RPM's get too low. Without the check engine light, it makes it a guessing game. It could be a MAF sensor, TPS sensor, IAC sensor, fuel pressure issue and the list goes on.