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Misfire, Rough acelleration, Hesitation
I bought a used 2007 Altima 2.5SE
The owner said he put on a new valve cover but it was running rough and he thought it needed a new ignition coil. I installed new ignition coils and spark plugs, but it was still running rough and giving PO300 Random Misfire It was very rough and shaky during acceleration, especially around 40mph I cleaned the MAF sensor, put in a new air filter. I then cleaned the throttle body and that seemed to help the most so far. I checked the valve cover and the gasket was broken so I replaced that with a new one. I also noticed many of the wires going to the ignition coil harness connectors were worn and exposed, so I replaced all the ignition coil harness connectors. It is running better, but still rough. When I am accelerating it seems like there is hesitation before it actually starts going. Then it is rough unless you really floor it. At 40mph, if you just coast it is smooth as silk. If you floor it to quickly go up to 60 it does ok too. but if you just try to keep a little throttle to maintain 40 it starts to shake and put-put-put. What else to check? Would really like to solve this problem, very annoying. |
#2
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Is P0300 still on? I would look for intake air or vacuum leak.
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#3
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Quote:
Quote:
I had a vacuum line fall off on another car, it was an easy fix because it was SO LOUD and easy to find. As soon as I popped the hose back on it ran like a top. This does seem like a similar situation, I'm just not sure where to look Edit: looks like I can pull the brake booster line and blow smoke in it.. yes? That will show if there is a leak? Edit2: Do I need to re-learn the throttle body since I cleaned it? Last edited by Pyper; 08-28-2018 at 06:34 PM. |
#4
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1. When you cleaned throttle body and disconnected the electric throttle harness you will need to do the Idle Air Volume Learning procedures.
2002-2011 Nissan Altima Idle Air Volume Learning Procedure | Nissanhelp.com After warming engine to NOT go to #5 &6 that is Cycle ignition switch 3 seconds On and at least 10 seconds Off. Key word is At Least....meaning you can be more but not less. Then go to #7, Do not rush you have plenty of time. You may need your phone's Stop Watch for correct count. #8 the MIL should blink in 10-12 seconds. If it doesn't in 15 seconds, start over. good luck |
#5
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I have tried several times to re-program the electronic throttle body. I'm not sure if I actually did it or not. The car still shakes between 20-45mph (cruising around town)..
I did a smoke test today (that almost killed me) and the only place any smoke came out was between the throttle body and the manifold.. I bought a new gasket and made sure it was sealed, but that didn't seem to change anything.. Time to take it to the Nissan stealership? I am running out of things to try. EGR valve? Fuel Filter? Edit: I will take a video tomorrow and post it so you can see what it is doing Last edited by Pyper; 09-05-2018 at 06:00 PM. |
#6
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Well, I went out to take a video and low and behold the error code changed to P0303 Cylinder 3 Misfire. I swapped the ignition coil and spark plug with cylinder 2, but I still get the P0303 error. What else to check?
Edit: upon close inspection, the wires going to the injector connector had came out! a $3 new connector from O'Reilly's and it is running smooth as silk! Yay! Last edited by Pyper; 09-09-2018 at 01:44 PM. |
Tags |
acelleration, hesitation, misfire, rough |
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