Hey I know the p0300 code is misfire on multiple cylinders and the misfire is coming from cylinders 1,3 and 5. I've replaced coil packs and plugs, cam position sensor, mass airflow sensors, computer and did a compression test and all checked out fine and the car ran fine for over a year or roughly a year and a hlf with the new parts installed. now all of a sudden it won't run over 30mph at 3000rpm with out sputtering. what is the next thing to try? also, i know it's not a fuel issue.
Did you use OEM MAF sensor? I would test the sensor first.
vacuum leak on bank 1
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Did your check engine light or service engine soon light come on? Scan it for codes see what came back after doing all those a repairs. That’s where I would start.
