1986 Mazda 323

Engine Performance problem
1986 Mazda 323 4 cyl Front Wheel Drive Manual 366000 miles

Engine bucks at upper RPM range when trying to accelerate. Mostly in the higher gears 3rd through 5th
July 6, 2009.

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include: Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

Jul 6, 2009.