Loss of power

2004 MITSUBISHI LANCER
19,000 MILES • 2.0L • 4 CYL • 2WD • MANUAL
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MICHAEL LECONA III
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When i drive some times it jumps and will not accelerate. if I give it more gas and makes it worse. No check engine light is on.It actually has 190,000 miles on it.
Apr 11, 2020 at 5:49 PM
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ASEMASTER6371
  • ✓Experienced Mechanic
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Good morning,

I would do some basic checks first.

https://www.2carpros.com/articles/engine-has-low-power-output

I would check the fuel pressure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I would also do a cat converter test to be sure the catalytic converter is not clogged not allowing the engine to breathe.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Roy
Apr 11, 2020 at 7:09 PM
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MICHAEL LECONA III
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How do i check the catalytic converter?
Apr 11, 2020 at 11:56 PM
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ASEMASTER6371
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You would need a back pressure gauge. You can get one at a parts store and remove the O2 sensor and install it. Start the engine and it will read a pressure. Anything greater than 1.5 pounds means it is clogged.

Otherwise, you could drop the head pipe to the exhaust manifold and then take it for a drive and see if it still has the issue.

Roy
Apr 12, 2020 at 12:02 AM
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MICHAEL LECONA III
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Up upstream or downstream?
Apr 12, 2020 at 12:10 AM
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ASEMASTER6371
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Upstream sensor.

Roy
Apr 12, 2020 at 12:12 AM
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MICHAEL LECONA III
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Someone told me that i can test it by taking the up stream o2 off to check it. do you think it safe to do?
Apr 12, 2020 at 12:17 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
That is not enough of a leak to test the back pressure.

Dropping the pipe is the best way to test it. Or, get the gauge and put it in the upstream O2 sensor hole and measure the back pressure.

Roy
Apr 12, 2020 at 12:19 AM
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