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Ask Amedee Your Own Question
Amedee, Former ASE Master Tech
Category: Car
Satisfied Customers: 24120
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
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when I accelerate my car sputters and jerks for a few ...

Customer Question

when I accelerate my car sputters and jerks for a few seconds then the rpms drop back and it slowly accelerates. It doesn't seem to have the same horsepower and the gas milage is dropping
Submitted: 9 years ago.
Category: Car
Expert:  Amedee replied 9 years ago.
Greetings! When was the last time the engine was tuned up? No, not just plugs, but a full tune up! The whole nine yards! This sounds like a classic ignition misfire! They usually go bad under a load like under acceleration, but can be noticeable at any time. It is very important to have your engine equipped with good tune up parts or you may be causing damage to other components of you car which can be expensive!
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Customer: replied 9 years ago.
Reply to AMEDEE's Post: So I should replace the cap and rotor and wires - anything else you consider full tune-up
Expert:  Amedee replied 9 years ago.
Plugs, wires, cap, rotor and maybe even ignition coil. This would be the complete secondary ignition system. Some shops like to do a pcv valve with the tune up. U can if u want, but this will not cause your engine to misfire.
Customer: replied 9 years ago.
Reply to AMEDEE's Post: one last question - a shop wanted me to bring in the car for a fuel system cleaning it is about 160.00 but for about 140.oo I can do the full tune up which one is the better option because I can't afford both.
Expert:  Amedee replied 9 years ago.
TO be honest, I would start with the tune up parts! Get good strong ignition components in there first!
Customer: replied 9 years ago.
Reply to AMEDEE's Post: the tune up didn't change anything - I noticed my air intake hose is cracked, could this be causing my problem of the car when I accelerate it jerks and lunges like it isn't getting enough gas in the engine like when you hit the gas it doesn't quite have enough in the engine and it is jerking then lunging and after it reaches 6000 rpm it calms down and the jerking lunging goes away.
Expert:  Amedee replied 9 years ago.
If you have a mass air flow sensor your engine will do this. This is very common and can cause you vehicle to loose power along with many other drive ability issues. First look for cracks or rips or anywhere air can enter the engine that is not accounted for by the mass air flow sensor. The air leaks must be taken care of before we move on! This is a very important sensor input to the computer. The mass air flow sensor uses a hot wire sensing element to measure the amount of air entering the engine. The MAF sensor then outputs an analog voltage signal to the PCM proportional to the intake air mass. The PCM calculates the required fuel injector pulse width in order to provide the desired air/fuel ratio. If the sensor is bad or there is air leaking in the enigne that is not accounted for by the mass air flow sensor than this air/fuel ratio will be off causing severe performance issues. In extreme cases, I have seen this problems cause a no start condition. The check engine light may even pop on if the sensor is bad, the snorkel is ripped or a tube has fallen off. This will result in a lean condition. Weather it be the sensor or the snorkel, you can even do it yourself!


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