Having just gotten rid of my 1999 Malibu for a much better Chevrolet Lumina, IF you are having periodic engine problems or not, at the earliest opportunity, check your Malibu's rather unusual side mounted engine mounts for loose bolts. Then torque them to the reccomended max, and use thread locker.

This is to save weight, I assume, since GMC never never skimps on quality, and the double high mounted engine mounts in a Lumina for the same engine were replaced by an in line with the torque rotation, single, low mount engine mount. Since the Mount has to be removed to replace a serpentine belt, many mechanics neglect to thread lock and properly torque the mounting. I WOULD ADVISE GETTING A TORQUE WRENCH AND LONG EXTENSIONS and checking the work yourself.

Engine vibration adds to the perfect storm of unique innovations tried on this engine, as the gasket torques, head and intake, are lowered to allow for differential metal expansion.

BTW, a good way to tell if your Malibu mechanic is a dud is, right after your oil change, ask to 'check the transmission fluid level'. If he doesn't start up the engine, raise it on a hoist, and check the fluid form underneath, don't go back.

Update from Sep 26, 2019: The BOLTS iirc ARE 10.9, GRADE, so be careful to thread them properly, as you can damage the softer metal in the mounts.

The Malibu's unique 'in line with the torque' mounting angle is something I've never had in a vehicle before. On the same engine, in the Lumina with the same engine, the angle is top and perpendicular, the twin mounts are held by a solid frame piece over the radiator, traversed braced.