Poor fuel mileage

2013 NISSAN SENTRA
131,111 MILES • 1.8L • 4 CYL • 2WD • AUTOMATIC
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COURTNEY CHARLSTON
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Car listed above is an SV model. I'm getting half of the gas mileage I use to get, the last tank fill up before this one, I got about 100 miles to the tank... used to get around 400.. 2 different tapping noises, one you can hear much more inside of the vehicle or below 1,500 RPMs, no power. It almost stalls when the A/C compressor kicks on, tachometer moves a little during idle. Car has been stolen and ran from the police at max speed and also has hit a deer. Almost everything plastic was broken, but pretty sure got most of it fixed.
Jun 9, 2022 at 2:32 AM
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JACOBANDNICKOLAS
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Hi,

If you hear a tapping from inside, it could be a faulty or partially plugged catalytic converter. Does the exhaust sound different than usual? Are there strange odors coming from the vehicle when it is running? Take a look through this link and let me know if anything discussed mirrors what you are experiencing:

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

Also, is the check engine light staying on when the engine is running? If it is, have the computer scanned for diagnostic trouble codes. Here is a quick video showing how it's done:

https://youtu.be/b2IJGfImVvw

If you don't have a scanner, most parts stores will do it free of charge.

Let me know.

Take care,

Joe
Jun 9, 2022 at 9:23 PM
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COURTNEY CHARLSTON
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None of the symptoms match. It also takes a second of turning over to start. I have the Zues in my car, and I only have one code, and it randomly comes on and goes off by itself. If I clear it, it may come back in a week or the next day. I did also add a cold air intake.
Jun 11, 2022 at 1:00 AM
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JACOBANDNICKOLAS
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Hi,

What code is it that turns on? Also, is there any dark gray or black smoke from the exhaust?

Let me know.

Joe
Jun 11, 2022 at 7:03 PM
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COURTNEY CHARLSTON
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P0448, which i just changed the valve and it is running a little better, tap is still there. No smoke.
Jun 11, 2022 at 8:55 PM
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JACOBANDNICKOLAS
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Hi Courtney, the code is for the evap canister vent valve. That shouldn't cause tapping. By chance, can you tell approximately where the tap is coming from?

Is the tap loud enough for you to record and upload for me to hear? That may be helpful for me.

As far as the evap code is concerned, there is a chance you still have a vacuum leak. That would cause a rough idle, but I don't feel it would cause the power loss.

Let me know if you can record the sound.

Take care,

Joe
Jun 12, 2022 at 7:44 PM
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COURTNEY CHARLSTON
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Honestly, I can't tell if it's coming from the top or bottom, or even both. When the car is below about 1,500 RPMs, you can hear it a lot louder. I will definitely check for a vacuum leak.
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Jun 13, 2022 at 6:33 PM
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JACOBANDNICKOLAS
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Hi,

Let me know if you find any leaks. I listened to the video, and I couldn't hear anything. I don't like asking this, but do you hear it in the video so I can pay closer attention at a certain point? I listened three times and didn't notice anything.

Let me know.

Jun 13, 2022 at 7:34 PM
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COURTNEY CHARLSTON
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At 7 seconds and at 19 seconds is when I am giving it gas and you can hear it. Doesn't sound like a tap in the video. I will try to take another.
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Jun 13, 2022 at 10:31 PM
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COURTNEY CHARLSTON
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Here's another one.
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Jun 14, 2022 at 7:12 PM
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JACOBANDNICKOLAS
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Hi Courtney,

I don't like to say this without being there, but to me, it sounds more like a knock than a tick I was able to hear it in your last video.

Make sure the engine oil is clean and full. Also, take a look through this link:

https://www.2carpros.com/articles/engine-noises

If you look at the last section which discusses the causes of a knock, you will understand why I don't like to say it's a knock without being there. Tell me. If you were to place the vehicle in gear, press hard on the brake, and gently on the throttle (placing the engine under a load) does the sound change?

Let me know.

Joe

Jun 14, 2022 at 7:45 PM