1998 Ford Ranger Rough running vehicle

Im a Mechanic at the Base here in Fallon, NV and we have this Government vehicle that runs poorly, when cold it wont idle. I have to hold the throttle until it warms up and then runs decent but poorly. It will drive but again poorly. I have a check engine with these codes: P1131, P1151, P1780, P1137, P0171, & P0174. My mecahnical knowledge tells me a dirty MAF or an Intake Manifold Gasket leak. But out here I can't do the old either method of finding the exact spot of the leak. Can you tell me if im right on the IMG leak and what to use to find it or just tear it apart and replace the gasket. Thanks!