The gas pedal or throttle stopped working
Your 2009 Mercury Mariner is a DBW throttle, "Drive By Wire". It has no mechanical linkage to the throttle body, it is controlled electronically by the pedal and ECU. OK, so that brings up several possible scenarios, fuse, rheostat, ground issue, wiring short. begin checking fuse. It's labeled on the cover of the fuse box. If a new fuse blows immediately, 1) DO NOT attempt to use a higher amp fuse. it's going to need a mechanic, maybe even the dealer because many shops do not have mechanics/technicians trained in DBW. Ford/Lincoln/Mercury won't release a lot of technical information because they want you at the Dealer to Lighten your wallet
David is on the right track, the most likely problem is the gas pedal sensor unit, have the codes pulled, if I'm right there should be one there for TPS range.
Forgot to mention, call your dealer as this may still be under emission warranty.
Thanks, will go have codes pulled, it's not fuse because I turned it off and started it 10 minutes Later then when I started it was like nothing ever happened
Looking for a Used Mariner in your area?
CarGurus has 920 nationwide Mariner listings starting at $1,250.
Search Mercury Mariner Questions
Mercury Mariner Experts