The plastic engine cover on the Fusion Hybrid has a little round door that flips up for access to the dipstick. If you leave the door open and close the hood, you'll crack the engine cover and maybe even break loose a wire coming from one of the black plastic posts sticking out of the top of the engine, which will make the engine run very badly. Great design. To prevent this: pull the cover off, remove the little round door, then put the engine cover back on. Needless to say, if you break one of those little wires, the warranty doesn't cover the repair. Live & learn.