Engine Performance problem
1996 Pontiac Grand Prix 6 cyl Front Wheel Drive Automatic 207350 miles
Over all it's been a very good car to my wife and I, but over the past 3 months or so we've been having some problems with the car Stalling! Or just dying out while driving. (It always started back up.)
On Tue.7-28-2009 I had a brand new Fuel pump and fuel filter installed, plus new Ignition control module and new spark plugs and plug wires. The battery and the alternator are six months old. After all that repair and new parts put in, YES! It runs so much better, but? I noticed it still hesitates and stumbles slightly. The Air Filter is K& N and is fairly new, so I'm wondering if maybe : installing a new PCV valve and new Throttle position sensor would help. Thanks for your help.
Hesitating, stumbling, jerking like a kangaroo can be caused by the following
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