What Causes a Car to Momentarily Lose and Regain Power While Driving?

[OliveRose]

Car momentarily losing and regaining power while driving is an issue with the alternator. The alternator may cause this fault due to problems with the carbon brushes or rectifier. In such cases, the only solution is to replace the entire alternator assembly. Below are detailed explanations about car alternators: 1. Introduction: The car alternator is the primary power source of a vehicle. Its function is to supply power to all electrical devices (except the starter) and simultaneously charge the battery when the engine is running normally (above idle speed). 2. Composition: Based on the three-phase stator winding of a standard AC alternator, additional winding turns are added with lead-out terminals, along with an extra set of three-phase bridge rectifiers. At low speeds, the output is from the original and additional windings connected in series, while at higher speeds, only the original three-phase winding provides the output.

[VonElla]

Last time I encountered the car suddenly losing power while driving and then recovering, I have to say the common cause is loose battery terminals. On bumpy roads with strong vibrations, the connection points may temporarily disconnect and then reconnect, causing a momentary power loss and recovery. It could also be due to corroded fuse holders or oxidized relay contacts causing poor connections. If the alternator belt is loose and slips, it may momentarily fail to generate electricity but quickly snaps back into place and recovers. Safety is quite important. If it happens once, it's recommended to stop the car and manually shake the battery cables to see if the lights flicker; regularly clean the terminals to prevent corrosion from spreading. If it happens multiple times, it's best to go to a professional shop to check if the alternator rectifier or ECU system is abnormal. Don't ignore small issues that could lead to big trouble.

[OAliyah]

When driving an old car, I once experienced the engine suddenly stopping and then restarting while on the move. After inspection, it turned out to be a worn ignition switch with loose contacts. The bumpy road vibrations caused a momentary power interruption and recovery. Similarly, battery cable terminals can also age in this way, especially after years of use when corrosion sets in at the connections. What I learned is to develop the habit of checking these myself: after parking, tighten the battery terminal screws; inspect whether the fuse box connections are secure. If it happens even once, don't take it lightly—perform a quick check first, then visit a repair shop for a thorough circuit inspection to ensure a safe and risk-free drive next time. Vehicle maintenance isn't troublesome; it saves worry and effort.

[MaggieDella]

A brief power interruption while driving is quite frightening and poses extremely high risks. The main cause is poor power contact, such as loose or corroded battery cables, which disconnect when the car shakes but reconnect instantly. Oxidized fuse sockets or relay ports can also cause this issue. The hidden danger is that it may fail again at any time, leading to engine stalling and stopping the vehicle. Immediately slow down, pull over safely, and check the battery connections and fuse box. Do not underestimate this issue, as it can affect power steering and increase the risk of accidents. After such an incident, be sure to have a technician conduct a comprehensive inspection—safety comes first.