What's wrong with speeding up in peugeot 3008?

There may be two reasons for the poor speed increase of the car: first, the engine fails; Second, the automatic gearbox is out of order: put the gear in P or N, start the engine, and slowly step on the accelerator to see if the speed can exceed 4,500 rpm and the speed increase is strong. If the engine speed cannot be increased or the speed increase is weak, it is judged that the engine is out of order. The following inspections are needed: check whether the high-voltage line, ignition coil, throttle opening sensor, engine speed sensor and their related circuits are faulty, and measure whether the cylinder pressure is normal. If it is low, it may be oil leakage in the cylinder. There are two reasons, one is that the valve is not closed properly; Second, the piston ring is badly worn due to improper engine maintenance, or the piston ring loses its elasticity due to excessive engine temperature (that is, the piston is surrounded by death). Check whether the engine control computer works normally. If there is nothing wrong with the engine, check whether there is something wrong with the automatic transmission: support the car on the hoist and check whether the automatic transmission oil is deteriorated. If the oil is deteriorated, stinks or contains powdery impurities, it means that the clutch plates in the gearbox are burnt out. If the gearbox oil is normal, put N gear, start the engine, observe whether the gearbox upshift is smooth, measure the oil pressure of each gear, and find out the gear with abnormal oil pressure. The reasons for the unsmooth transmission upshift may be: the upshift and downshift valve is stuck or the upshift solenoid valve is out of control.