# 2001 Altima - End of my rope



## Navigator (Sep 27, 2013)

Hello Forum,

New poster here, and in desperate need of some help. I have a 2001 Altima and need to rely on it as my other vehicle was wrecked. She was running fine till the knock sensor broke, replaced that. Also threw an O2 sensor code that mysteriously went away when I replaced the KS. Same for the "ghost" Mass Air Flow sensor error. Passed emissions so I assume it is was a fluke. Then the P0304 error popped. Changed all the plugs, wires and distributor cap. Error is now P0300. So I bought 4 new injectors. engine still runs very very rough at idle and will stall. Runs fine above 1k rpm. I'm not a novice mechanic but neither am I a pro so I did this under the tense gaze of my veteran mech. father...you can imagine how enjoyable that was for me. 

TL;DR version:
P0300 error, rough idle, need suggestions / advice / counseling. I need this car to last till I can get a new one.


Thanks for any and all help offered!

Fair winds and following seas.


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## rogoman (Dec 16, 2004)

Several things to check:
- Sticking EGR valve.
- Check the fuel pressure.
- Check the crankshaft position sensor inside the distributor and the harness connector. See if the sensor has a lot of oil on it.
- Check for a vacuum leak by using a vacuum gauge.
- Check the MAF and it's harness connector. The MAF hot wire might need cleaning.


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## smj999smj (Jan 1, 2006)

Might also be a leaking intake manifold gasket. They aren't as common on L30's as they are on U13's, but possible. Try spraying some carb cleaner in that area and see of the RPM raises. If so, it's likely your problem.


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## Navigator (Sep 27, 2013)

*Altima*

Thanks for the suggestions, will get to work on it now that I'm home for a while. Odd thing today when I drove the car about 50 miles total, SES light was not on. Could P0300 code have been a default trouble code for the rough condition?


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## smj999smj (Jan 1, 2006)

P0300 is a code for random misfire. If the engine is running rough, it is usually misfiring, so the code makes sense.


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## BeyondBiscuits2 (Jan 18, 2006)

I'd second the intake manifold leak. This is a notorious problem on the KA24DE and first-gen QR25DE. If I am not mistaken, and I could be, there was also issues on the first-gen QR25DE about sucking in butterfly valve screws that can cause all sorts of issues.


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