# No Power Altima 01 GXE



## rcross5 (Nov 16, 2014)

I need some help, two days ago my 01 Altima started having almost no power when i gave it gas, it seemed to have trouble shifting until I gave it a lot of gas. No check engine light. I did some research and asked some advice and they led me to change the MAF sensor, which i did with no solution to my problem. What do you think?


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## smj999smj (Jan 1, 2006)

I think you shouldn't waste money on replacing parts unless you have some proof that they are bad. There are a lot of things that can cause a lack of power and without a scantool to view datastream, it can be hard to diagnose. Based on your description alone, the problem could just as easily be a transmission problem or a restrictive exhaust (ie bad catalytic converter) as it could be an engine or engine management problem. 
If I believed it was an engine issue, I would start by checking the basics. Check your spark plugs, wires, distributor cap (check for oil residue inside the cap) and rotor. Check/adjust your ignition timing with a timing light (if the timing is significantly off, you may have a jumped timing chain issue). Check your air filter. Use a fuel pressure gauge to check your fuel pressure and confirm that it is within specs and that your fuel filter is not in need of replacing. Do a compression test. Scan ECM datastream data, which would require a scantool.
If I thought it was a transmission issue, the obvious thing to do would be to check the fluid to see if it's burnt or off-color and/or if there are signs of debris or shiny metal flakes in the fluid. I'd make sure the cable and linkage were in good shape and properly adjusted. I would then have to use a scantool for datastream info or possibly a set of pressure gauges to view hydraulic pressures. 
If I thought it might be a restricted exhaust issue, then I would perform a visual check of the exhaust system followed by an exhaust back pressure test.
How much of this you can do on your own, I can't answer. There are times when having an experienced auto technician diagnose a problem is cheaper than guessing and swapping parts.


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## rcross5 (Nov 16, 2014)

I pulled the codes. It pulled P0100 Mass air flow and P0325 Knock sensor. I already changed the mass airflow though, so would it possibly be a connection issue with it? Evidently the Knock sensor is an infamous problem with these cars, what is the best way to go about rectifying that problem?


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## smj999smj (Jan 1, 2006)

It would have been good to know if the P0100 code existed before you installed the new MAS. Was the code memory erased after the new MAS was installed? If not, we could be looking at an old code. Also, a P0100 code doesn't necessarily mean the MAS is bad; it could mean there is a problem with the MAS circuit. If we don't know if the code was there prior to the new MAS install, it's also possibly that the new part is triggering the code. My suggestion would be to erase the codes, drive the vehicle and then check to see if the P0100 code came back. If so, then I would get the factory service manual diagnostic procedure for DTC P0100 and follow the diagnostic steps to find out exactly what the problem is. 
As far as the P0325 knock sensor code, it can be triggered when an engine is not running well. A bad knock sensor in itself will not cause a driveability issue. The general rule is that if a knock sensor code is triggered with another code, diagnose the other code first, erase all codes after repair, and see if the knock sensor code returns. If it does, there may be a bad knock sensor or shorted/open knock sensor circuit.


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## rcross5 (Nov 16, 2014)

I appreciate all of the info so far, I had the coded cleared and now only the P0325, so the plan at this point is to go through the diagnostic protocol for the knock sensor and see where my problem lies with that. Ive read that if the sensor is bad that there will be a severe lack of power, which is what I've been experiencing for the start, is the true.

thanks for you time.


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## rcross5 (Nov 16, 2014)

Also, I've been reasearching to be sure that the Knock sensor is the cause of my problems. I found this individual who seems to be having the same problem as me. 

loss of power on acceleration - Page 2 - Nissan Forums : Nissan Forum

that is no power at acceleration and no power under a load. He changed the Coolant Temperature sensor and it seemed to fix the problem. Whats the chance that this is whats causing the P0325?


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## smj999smj (Jan 1, 2006)

Anything's possible, but that's why sometimes it's tough to diagnose a problem without have a scantool to view the datastream info, such as the ECT sensor reading.


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## rcross5 (Nov 16, 2014)

Yeah thats what I've been finding, I replaced the Knock sensor which had a major crack in it. But no it seems like the car won't even turn over. I'm about ready to take it to someone.


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## rcross5 (Nov 16, 2014)

It no longer throws any codes but the problem persist


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