Last of the loud years — the recalls do more of the work here, so verify all six.

Recall 20V-668 covers the 2018 Malibu among many GM models: the stop/start transmission accumulator endcap may be missing bolts, which can leak transmission oil and progress to a loss of propulsion, and — with an ignition source — a fire. Dealers inspect the accumulator and replace it if bolts are missing, free. Because the symptom is a slow transmission-fluid leak, it's easy to miss on a used car; confirm this recall is closed and look for fluid seepage.

Still the loudest organic cluster: an interrupted accelerator-pedal-position-sensor connection drops the car into reduced-power limp mode (cut acceleration, Check Engine Light, 'Engine Power is Reduced' message, code P2138). GM's Special Coverage — a free extended repair program — reaches the 2016–2018 Malibu. On the 1.5T there is also a separate reduced-power cause, the charge-air-cooler outlet duct disconnecting from the throttle body (GM service bulletins cite codes P0101/P0172/P0299/P0506/P1101). Confirm the pedal Special Coverage was done and treat any reduced-power message as unresolved.

Two brake items. The vacuum-pump hard-pedal pattern (code P1101, GM 'increased brake pedal effort' bulletin) carries into 2018 as on the earlier cars. Separately, recall 18V-576 covers a rear brake caliper piston with insufficient coating that can form gas pockets and reduce rear braking; the free remedy is a brake-system bleed. Test the pedal firmly with the engine off then running, and confirm 18V-576 is closed.

The GM 'Shift to Park' false message appears here too — the car reports it isn't in park when it is, sometimes blocking shutdown and draining the battery. On the low-volume 2018 hybrid, the complaint file adds stalls where a dealer told the owner the car was 'confused' between running on the battery and the combustion engine, plus fuel-injector failures. Neither the shift-to-park issue nor the hybrid stall has a clean recall fix; a repeated pattern is a known headache, not a fluke.