When I start up my Max, I have to rev the engine for a sec or else the RPM's get really really low and it feels like it is about to stall out. It especially does it if I'm parked in my driveway (which is slanted a bit). But it'll do it even if I'm not on a hill.

I just had my 90,000 mile tuneup about 1 1/2 months ago, but it's still doing it. What could be the problem?

 

seems like the MAF sensor