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Topic
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I have a 2001 Nissan Altima 150000 miles.
When I start the car in the morning (or extended period of time) it will start and run a little rough at first but a minute or so sounds fine at idle (no problem here approx. 1000rpm ). The problem I have is if you accelerate there is a noticeable misfire. I have found if I warm the car and make sure the rpm can accelerate over 3000 rpm I can drive without issue the remaining day. During misfire I have received P0300, and sometimes a P0420. I do not really need the codes to tell me there is a misfire. If misfiring while driving the car will sputter, buck etc.
I have replaced catalytic converter, distributor cap, rotor, spark plugs, plug wires, fuel filter, sprayed carb cleaner around intake manifold looking for vacuum leak, checked compression dry only, added injector cleaner to tank, none of which seem to have improved my problem. I am not losing Coolant and the car is fun to drive after warm up. If the warm up didn’t take nearly 20-30 mins I don’ think this would be such an issue but weather gets colder here in Ohio and this issue seems worse in the cold, and this being my 16 year olds car patience is not his strong suite.
Thank you for spending time to read my problem,
Tom
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Replies
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Get the car hooked up to a scanner. See what the Intake Air Temperature sensor is reading as well as the Coolant Temperature sensor… See when it is going into closed loop… You may have a fuel mixture problem causing rough running. The warm up time being 20-30 minutes suggests something may be wrong with your thermostat… This has been a known problem to cause issues on Chryslers…. May be the same with your vehicle… Also a P0420 after the cat has been replaced may be O2 sensor related (downstream sensor, but this does not effect driveability)…. If you used an aftermarket replacement cat, those can also cause this…. A Scanner would help assist your troubleshooting… If your car has a MAF sensor, It may need cleaned or replaced, may also be EGR related… A vacuum gauge may also be helpful…
-Karl
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