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issues with my 350z

2K views 15 replies 3 participants last post by  Balthazar9000 
#1 ·
so hello my name its Bryan and I own a 2003 350z, last year I had an issue that when the car was in idle, the car would start making a nocking and popping sound and the oil pressure would go all the way to the top. so I took it to the mechanic and he end up telling me that It was the oil pump and the timing chain needed to be replace. so I end up taking it to him this year and he end up changing the oil pump and the timing and after all. the car kept making the same nocking and popping sound. so he told me that it was better to change the engine, so I agree to change it , he end up putting an engine with 77k and after he replace it the car came with the situation of doing the same problems it was doing with the old engine.. has anyone had the same issue or solution to this situation?
 
#6 ·
P0300 indicates multiple cylinder misfires and this is usually not an engine failure. The fact that you still have the same symptoms seems to indicate you STILL have the same electronic issues. Did you check the 02 sensors and harness wiring before replacing the engine?
 
#7 ·
Yes the harness and the 02 sensors were good .. like that’s what I don’t understand what’s causing this issue .. cause to have the same symptoms of the old engine the means that the old engine was good and was not the issue of the timming been off .. cause on the new one nothing was touch besides installing it.
 
#14 ·
So today I empty out the gas and put fresh gas and the popping and knocking sound wasn’t loud it was more less and not loud but I noticed that it was only making the popping sounds from the left exhaust. Cause when you touch the right exhaust the air was coming normal but on the left side it was coming out with pressure. And it keeps only getting the code p0300 for multiple misfires
 
#16 ·
So I had the P0300 and my engine was running badly and it turned out to be a bad O2 sensor even though it didn't throw a code specifically for that. I have a 2004.5 which has wideband upstream O2 sensors. I believe the 2003 has narrow band but I'm not sure if thats relevant. About the high oil pressure reading, when those sensors go bad they read full high on the gauge.

Since the symptoms only seem to occur in one bank my money is on a bad O2 sensor. You could switch the sensors and see if the problem follows it, just replace it, or read the live data with a scan tool and look at the O2 sensor voltages. Should be about the same voltage unless you have my year in which case the voltage of one is supposed to be half of the other. I don't know why they did that.
 
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