02 very sluggish at start
02-08-2013, 12:06 AM
#1
Thread Starter
Join Date: Feb 2013
Location: Texas
Posts: 4
02 very sluggish at start
Okay so i just bought a 02 GT w/ 140xxx on it. And to me it seems very very sluggish at the start till i get to about 40mph then once it kicks into 3rd (automatic) it seems to just take off. Any ideas to what maybe causing this?
02-08-2013, 07:07 PM
#6
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
When were the spark plugs last changed? At 140k it should have been at least 40k miles ago.
When was the motor and transmission fluid last changed?
When was the differential oil last changed?
I.e. the first thing to do is a complete tune up. Plugs, COP boots, engine oil and all other fluids.
If you do not know the car's history change the front O² sensors, at 140k miles they are more than shot. As they age their output voltage drops which tell the PCM the mix is lean when it really isn't. The PCM then richens the mix, making it too rich and causing the engine to bog under light acceleration. These rich short term fuel trim are accumulated by the adaptive learning algorithms and will affect open-loop operation as well.
Disconnect the battery for 5 to 7 minutes to reset the KAM (Keep Alive Memory) and see if it gets a bit better...
02-09-2013, 01:08 AM
#7
Thread Starter
Join Date: Feb 2013
Location: Texas
Posts: 4
When was the air filter last changed/cleaned?
When were the spark plugs last changed? At 140k it should have been at least 40k miles ago.
When was the motor and transmission fluid last changed?
When was the differential oil last changed?
I.e. the first thing to do is a complete tune up. Plugs, COP boots, engine oil and all other fluids.
If you do not know the car's history change the front O² sensors, at 140k miles they are more than shot. As they age their output voltage drops which tell the PCM the mix is lean when it really isn't. The PCM then richens the mix, making it too rich and causing the engine to bog under light acceleration. These rich short term fuel trim are accumulated by the adaptive learning algorithms and will affect open-loop operation as well.
Disconnect the battery for 5 to 7 minutes to reset the KAM (Keep Alive Memory) and see if it gets a bit better...
When were the spark plugs last changed? At 140k it should have been at least 40k miles ago.
When was the motor and transmission fluid last changed?
When was the differential oil last changed?
I.e. the first thing to do is a complete tune up. Plugs, COP boots, engine oil and all other fluids.
If you do not know the car's history change the front O² sensors, at 140k miles they are more than shot. As they age their output voltage drops which tell the PCM the mix is lean when it really isn't. The PCM then richens the mix, making it too rich and causing the engine to bog under light acceleration. These rich short term fuel trim are accumulated by the adaptive learning algorithms and will affect open-loop operation as well.
Disconnect the battery for 5 to 7 minutes to reset the KAM (Keep Alive Memory) and see if it gets a bit better...
02-09-2013, 03:49 AM
#8
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
Do the plugs too, at least pull them out and check them. They may even at 140k miles still be the originals, as the COPs are capable of firing across two 16d nails set 1/2" apart. This doubly important because when the plugs get very bad the COPs will overheat and burnout, or at best be weakened and burnout later on--and they are not cheap...
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