[PMC the 1st]

The phonomena the topic starter describes is very similar to a related phonomena: psychosomatic illness.

If you suffer from psycosomatic illness and you think the car is going to perform erratically, then it most certainly will.
Nothing the author of this thread can be traced to a minor engine fault; hesitation even upon light acceleration points to bad piston rings or bad valves, which is a fault that happens with high-mileage engines only. For this reason, I made my diagnosis. The diagnosis is not with the car, it's with the owner of the car.

There are two solutions to this problem. The first is a prescription for any of the benzodiazepine-based tranquilizers. These chemical compounds are designed specifically to assuage any anxieties the sufferer may encounter (and psychosomatic illness is a form of loosly-associated anxiety). After taking these benzodiazepines, the OP's Malibu problems will disappear. The second solution is to buy a different car altogether; one that isn't prone to induce anxieties in the OP when purchasing or driving.

To the OP, I suggest he buys the Accord or the Camry. Even if there is a serious engine problem with any of those two cars, his mind will likely not notice it...