Codes, Need Help Trouble Shooting
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gangstaCL03
Joined: Oct 2003
Posts: 92
Likes: 0
From: Philly, PA
Codes, Need Help Trouble Shooting
Took the whip down to autozone to have the codes read.
(PO420 and P1129)
Symptoms:
1. While driving, the car idles funny, alternating between 500 and 2000 RPM.
2. While Braking to a stop, it felt like the car was accelerating on its own as if I were pressing down on both the gas and the brake pedal at the same time
3. As the brake pedal is released, and with no foot on the gas pedal, the car feels as if I am actually pressing on the gas pedal (jumping foward, not a tranny issue however)
Note:
I've just replaced the autotranny at the dealer under warranty (4th time) and let the car sit waiting to be sold so it hasn't been driven since the "Operation" anymore than 25 miles. Therefore I doubt a tranny issue.
The 1st Code indicates that the Manifold Absolute Pressure (MAP) is higher than normal. Possibly caused by a dirty or failed MAP sensor, or a damaged vacuum hose.
The 2nd Code indicates that the PCM has determined that the catalyst system efficiency for bank 1 is below threshold. Possibly caused by a defective cat, engine misfire, large vacuum leak, or engine oil leakage into exhaust-valve guide seal and piston rings (which i doubt).
MY QUESTION:
Is it possible that the improper functioning of the MAP sensor can cause the CAT to be inefficient? Or are they unrelated issues?
Also, Would poor exhaust flow accelerate the wear of the CAT because of too much back pressure? ( I removed the resonator and left the stock mufflers on the vehicle, The car makes a horrible raspy noise when driving cold, but as the engine warms up to the proper operating temperature the noise goes away as the muffler's baffles expand)
I would very much appreciate any insight as to how this issue should be diagnosed. Replace the CAT and the MAP? or Clean the MAP and hope the CAT is still good? Any suggestions people
Thanks guys
(PO420 and P1129)
Symptoms:
1. While driving, the car idles funny, alternating between 500 and 2000 RPM.
2. While Braking to a stop, it felt like the car was accelerating on its own as if I were pressing down on both the gas and the brake pedal at the same time
3. As the brake pedal is released, and with no foot on the gas pedal, the car feels as if I am actually pressing on the gas pedal (jumping foward, not a tranny issue however)
Note:
I've just replaced the autotranny at the dealer under warranty (4th time) and let the car sit waiting to be sold so it hasn't been driven since the "Operation" anymore than 25 miles. Therefore I doubt a tranny issue.
The 1st Code indicates that the Manifold Absolute Pressure (MAP) is higher than normal. Possibly caused by a dirty or failed MAP sensor, or a damaged vacuum hose.
The 2nd Code indicates that the PCM has determined that the catalyst system efficiency for bank 1 is below threshold. Possibly caused by a defective cat, engine misfire, large vacuum leak, or engine oil leakage into exhaust-valve guide seal and piston rings (which i doubt).
MY QUESTION:
Is it possible that the improper functioning of the MAP sensor can cause the CAT to be inefficient? Or are they unrelated issues?
Also, Would poor exhaust flow accelerate the wear of the CAT because of too much back pressure? ( I removed the resonator and left the stock mufflers on the vehicle, The car makes a horrible raspy noise when driving cold, but as the engine warms up to the proper operating temperature the noise goes away as the muffler's baffles expand)
I would very much appreciate any insight as to how this issue should be diagnosed. Replace the CAT and the MAP? or Clean the MAP and hope the CAT is still good? Any suggestions people
Thanks guys
Intermediate
Joined: Jul 2008
Posts: 38
Likes: 0
Took the whip down to autozone to have the codes read.
(PO420 and P1129)
Symptoms:
1. While driving, the car idles funny, alternating between 500 and 2000 RPM.
2. While Braking to a stop, it felt like the car was accelerating on its own as if I were pressing down on both the gas and the brake pedal at the same time
3. As the brake pedal is released, and with no foot on the gas pedal, the car feels as if I am actually pressing on the gas pedal (jumping foward, not a tranny issue however)Note:
I've just replaced the autotranny at the dealer under warranty (4th time) and let the car sit waiting to be sold so it hasn't been driven since the "Operation" anymore than 25 miles. Therefore I doubt a tranny issue.
P1129
The 1st Code indicates that the Manifold Absolute Pressure (MAP) is higher than normal. Possibly caused by a dirty or failed MAP sensor, or a damaged vacuum hose.
The 2nd Code indicates that the PCM has determined that the catalyst system efficiency for bank 1 is below threshold. Possibly caused by a defective cat, engine misfire, large vacuum leak, or engine oil leakage into exhaust-valve guide seal and piston rings (which i doubt).
MY QUESTION:
Is it possible that the improper functioning of the MAP sensor can cause the CAT to be inefficient? Or are they unrelated issues?
Also, Would poor exhaust flow accelerate the wear of the CAT because of too much back pressure? ( I removed the resonator and left the stock mufflers on the vehicle, The car makes a horrible raspy noise when driving cold, but as the engine warms up to the proper operating temperature the noise goes away as the muffler's baffles expand)
I would very much appreciate any insight as to how this issue should be diagnosed. Replace the CAT and the MAP? or Clean the MAP and hope the CAT is still good? Any suggestions people
Thanks guys
(PO420 and P1129)
Symptoms:
1. While driving, the car idles funny, alternating between 500 and 2000 RPM.
2. While Braking to a stop, it felt like the car was accelerating on its own as if I were pressing down on both the gas and the brake pedal at the same time
3. As the brake pedal is released, and with no foot on the gas pedal, the car feels as if I am actually pressing on the gas pedal (jumping foward, not a tranny issue however)Note:
I've just replaced the autotranny at the dealer under warranty (4th time) and let the car sit waiting to be sold so it hasn't been driven since the "Operation" anymore than 25 miles. Therefore I doubt a tranny issue.
P1129
The 1st Code indicates that the Manifold Absolute Pressure (MAP) is higher than normal. Possibly caused by a dirty or failed MAP sensor, or a damaged vacuum hose.
The 2nd Code indicates that the PCM has determined that the catalyst system efficiency for bank 1 is below threshold. Possibly caused by a defective cat, engine misfire, large vacuum leak, or engine oil leakage into exhaust-valve guide seal and piston rings (which i doubt).
MY QUESTION:
Is it possible that the improper functioning of the MAP sensor can cause the CAT to be inefficient? Or are they unrelated issues?
Also, Would poor exhaust flow accelerate the wear of the CAT because of too much back pressure? ( I removed the resonator and left the stock mufflers on the vehicle, The car makes a horrible raspy noise when driving cold, but as the engine warms up to the proper operating temperature the noise goes away as the muffler's baffles expand)
I would very much appreciate any insight as to how this issue should be diagnosed. Replace the CAT and the MAP? or Clean the MAP and hope the CAT is still good? Any suggestions people
Thanks guys
.
Team Owner
Joined: Sep 2006
Posts: 33,535
Likes: 1,142
codes are NOT diagonosis they are merely clues to the real problem
Start with checking whatever you did last to the car
What made it start doing this
You describe a vac leak and possible Throttle Body Control problem-it happens
Have a muffler shop check the cat
Sometimes you have to pay acura and get a correct diagnosis before dropping 500-1000 on parts
Start with checking whatever you did last to the car
What made it start doing this
You describe a vac leak and possible Throttle Body Control problem-it happens
Have a muffler shop check the cat
Sometimes you have to pay acura and get a correct diagnosis before dropping 500-1000 on parts
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