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Acceleration problem - 2000 Corolla

6320 Views 7 Replies 5 Participants Last post by  Ukrainian102
For the past month, whenever I first start the car and press on the accelerator it barely moves. The accelerator has to be lightly pumped and then it will take off. Once the car has be driven continuously for a couple minutes, without stopping, it drives without problems. This started happening sporadically and has increased to every time the car is cool. There is also a very thick black residue in my tail pipe.

The front oxygen sensor gave a correct reading and according to the book I have, the back does not do much. All other maintenance is up-to-date. However, the mass air flow sensor stalled the car whenever a slight shot of air was blasted to it. Is that normal? I have seen other threads with similar problems, but no solutions. Please anyone who has solved this problem tell how you did it, I am begging!!!!!!
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oil could be clogging up something considering that you have that residue in your tailpipe, the oil could be leaking in the engine
My 2000 Corolla has exactly the same problem. There is no residue in the tail pipe but the behavior is exactly as you described. That means the residue has nothing to do with the problem.
Unfortunately I am also unable to pin point the problem.
it must be a faulty sensor or maybe an injector...

but usually a problem like that will throw a code..
and you aren't getting a check engine light?
The cause for the residue would be your motor running rich. If it was lean, it would burn up everything and have hotter than normal exhaust. By running rich, not all the fuel is burned and that is left behind in the tailpipe. When you blew air on the air flow sensor, the engine computer tried to adjust by injecting more fuel, but since you werent actaully blowing the air into the engine, it resulted in a mix too rich to run and it stalled. But since its all fuel injected, to change all this I would think somehow the computer would have to be reprogrammed. The only reason it should be having these problems is if you are at a high altitude. There are less air molecules and therefore the motor runs richer. Temperature and humidity have something to do with it too, but it shouldnt be a problem at all. A car with fuel injection and a computer should be able to automatically adjust. I would say check all the sensors that need to be checked that have to do with the intake and exhaust, and check the computer. Often the computer adjusts the mixture depending on the exhaust sensors downstream, to tell how thoroughly the fuel is being burned.

Check that computer! Check that all the sensors are returning normal readings. mass airflow, manifold absolute pressure, o2, manifold air temperature, and throttle position. Those are the senors related to a fuel injection system. I don't know if its possible to check all of them. the sensors should be operating in a closed loop, where the computer adjusts various things to automatically compensate for the changing sensor readings.
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UPDATE: It is getting progressively worse and no one has the slightest clue what is causing this. There have been 2 trouble codes, PO300 Random/Multiple Cylinder Misfire and PO171 System too Lean. However, 171 occurs more often and I have a feeling that these are just symptoms of the problem. All sensors readings are normal. Most likely, this is not just a part failure because it has been getting worse and the car runs perfectly when warm. If something had just failed the problem would stay the same and probably cause additional trouble.

Anyone?? Anything??

Dude, take it to a dealer/Toyota mechaninc. It's worth the money to get it fixed.
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