I just had both these codes on my 1998 Bonneville. Since I do not have the means to run the tests that the factory manual suggest, I went looking for vacuum leaks. Found my MAP sensor'* rubber seal was pushed down into the PCV housing and not on the MAP barb. I replaced the MAP that of course came with a new seal and it fixed it.
But I would do as suggested above, check for vacuum leaks around the throttle body (squirt with a carb cleaner while running, idle will rise if the carb cleaner momentarily fills a leak). Also take the PCV top off which the MAP is plugged into and make sure it is all sound. Also while you're at it change the PCV valve, only $2.50 and it is before the MAP and could cause anomolies.
Last edited by Bigfoot; 02-04-2009 at 11:30 PM.