I have a 2008 altima coupe. When the car has been

A bad motor or cable what ever makes the seat recline . Viewing a repair manual an seeing what is broken is how to find the problem . https://www.nicoclub.com/FSM/Altima/2008/se.pdf

ANSWERS: Oil Loss, Buzzing Noise, ETC. - Nissan Forum ' Nissan Forums

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Mar 20, 2008 - 3) Yet another buzzing, rattling or whinning noise. If you own a Quest van, Maxima, Altima 3.5 and some Z/G/FX vehicles, and get a loud ... Mysterious no-spark situation with a buzzing transmission
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Buzzing noise at 2000-3000 RPM - Nissan Forums : Nissan Forum

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Oct 28, 2003 - 6 posts - ‎3 authors
The "buzzing noise"; I can tell that I am not alone in having this problem but has someone figured out ... I fit does, that eliminates the brake rotors, tires, wheelbearings, CV's etc. ... BUT with an Altima it is probable the pre-cats. Loud humming noise when driving
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so your inquiry is about the tach?

No. There are several reasons why there is a muffler on your car in the first place. First of all is noise. No offense or anything but your car roaring down the road like a noisy piece of junk isn't cool.
Second, the engine is tuned to operate optimally with the muffler attached. Removing it will screw up the pressure ratio for your engine and will mess with your engine.

This is a ?tupid modification that isn't going to do anything but make a bunch of awful sounding noise and reduce your engines power output. Spend your time and money doing something else that is actually benefiting your car. Nice speakers, better tires, better fuel. Don't waste time or money on messing up your car.

A vehicle that slows down and accelerates on it's own, sounds as though it is having issues with the cruise control. It slows itself down and speeds up in order to maintain the designated speed. That is where I would start my diagnosis.

Nissan's 2008 Altima was offered in several trim levels, ranging from the base 2.5-liter four-cylinder model to the sportier 3.5-liter V-6 Coupe. While the high-end trim levels were equipped with a premium Bose-developed nine-speaker sound system, lower-end Altima models were fitted with a standard six-speaker system mated to a single-disc CD player.-------------------------------------------------------------------------------
Digiprog 3

Don't know if a trans shop will work on a CVT--- we didn't
when I had my shop

May have to go to dealer

If it sounds like it is coming from the outside of the car I would suspect one of the plastic inner fenders or the cowl on the front of the car flapping in the wind. If you can, have a friend drive along side of you with their window down to help pinpoint the location of the sound. The sound appears to be random so I wouldn't think it was electrical or mechanical.

it could be the ignition coils spark plugs or the timing, would have these checked.

Sounds like you have a bad connection at the blower motor plug. Have you checked under the glove box where the blower motor is? Usually has a big plug with 2 heavy gauge wires. that might be melted or getting a bad connection. Try holding the plug to one side or wiggle it to see if turns off blower. If not, check your resistor that controls your fan speed, located near the fan on your a/c ducts. Usually has a plug with 4 0r 5 wires held up by 2 screws. The wires are heavy gauge as well