1999 Subaru Other

Engine Performance problem
1999 Other Subaru Models 4 cyl All Wheel Drive Automatic 124480 miles

I have a catback exhaust and a short ram air intake on it! Nothings really wrong I just want to stop the normal accelerator lag! For example when I'm at a stop and stomp on the gas the motor falls on it's face then takes off. If you can tell me what part/parts I can add or what mods I can make to stop the accelerator lag it would be greatful! Thanks!
July 31, 2009.

Your problem could be caused by the following: Oxygen sensor
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

Aug 1, 2009.