You won't be able to replace the MAF sensor because your car doesn't have one. Code 34 in your car means "Manifold Absolute Pressure (MAP) Sensor Circuit - signal voltage low" In the 3.0 and 3.3 it's the other meaning. So you either have a problem with the sensor or with your vacuum system. I'm thinking more of an obstruction rather than a leak (given the MAP value is high).
All the vacuum system does is use the vacuum created in the trottle body (by the suction of the engine) for other applications (power brake, EGR valve).
A fairly simple system, just check all the black hoses (some fuel lines might be black too, never hurts to check too much here) coming out of the Trottle Body for cracks, check the TB if there are uncovered openings. Check for a hissing sound around the TB, could mean a bad gasket
If you can't find anything obvious, you could get a vacuum tester, but you can easily feel the suction with your finger. If there is plenty of suction it might just be the sensor (about $30)
There is a test for the MAP, but that test more the whole vacuum system, rather than just the sensor. If needed, I'll post it.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.