What is the reason for normal acceleration in neutral but abnormal acceleration in gear?

[ColinRose]

Normal acceleration in neutral but abnormal acceleration in gear is caused by a faulty fuel pump, which requires professional inspection, repair, or replacement. Below are specific details about the fuel pump: Principle: The fuel pump is a component that draws gasoline from the fuel tank and delivers it through pipelines and the fuel filter to the float chamber of the carburetor. It is because of the fuel pump that the fuel tank can be placed at the rear of the vehicle, far from the engine and below the engine. Application: In summary, whether it's airplanes, rockets, tanks, submarines, drilling, mining, trains, ships, or daily life, pumps are needed everywhere and are in operation everywhere. This is why pumps are classified as general machinery and are a major product in the mechanical industry.

[GiannaLee]

I encountered the exact same issue when repairing my car last year. The engine revs up smoothly in neutral, but once in gear, it just falters. It's most likely the clutch disc is worn out, just like a bicycle chain slipping when pedaling. When in gear, the engine has to pull the entire vehicle; if the clutch can't grip properly, power loss occurs. Try starting on a slope first—if you smell burning and the car rolls back, it's pretty much confirmed the clutch is done for. It could also be a stuck throttle cable, but that's less probable. Ignoring this kind of fault is particularly damaging to the car, and eventually, you'll end up replacing the entire pressure plate assembly. Hurry up and find a repair shop to lift the transmission—a roadside stall's 500-yuan labor fee should be more than enough.

[CatherineMarie]

I encountered this issue with my old Jetta, and it boils down to three key points: intake/exhaust, fuel supply, and ignition. Shifting gears requires more air intake—if the air filter is clogged like a mask or the exhaust pipe is blocked by shattered catalytic converter debris, the car wheezes like it's having an asthma attack. For the fuel system, focus on checking the fuel filter; neglecting to replace it for two years can starve the fuel injectors. The most extreme case I've seen was a cracked ignition coil—it idled fine, but as soon as you shifted gears, high-voltage electricity would leak onto the engine block. Troubleshooting is straightforward: try a new air filter for a couple of days; if that doesn't work, remove the front section of the exhaust pipe and take it for a spin. If the problem persists, just go straight to reading the trouble codes.

[DonovanFitz]

It depends on the specific symptoms. If pressing the accelerator after shifting gears feels like stepping on cotton and the speed takes forever to pick up, it's likely clutch slippage. If the engine jerks and coughs, check if the spark plugs are clogged with carbon deposits. The trickiest one I've fixed was a worn-out crankshaft position sensor - when it overheats, it sends erratic signals, confusing the ECU about fuel injection timing. Beginners often get tricked into replacing the throttle body, which usually isn't necessary. I recommend keeping a can of carburetor cleaner handy; sometimes just spraying the intake pressure sensor twice solves the problem when it's clogged with sludge.