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Hey guys I’m having trouble finding out how to fix this p0300 code I have on my 96 LT4 there are no other codes accompanying it and the misfire is noticeable at idle once the engine is warm starts around 150-160 degrees and gets noticeably worse as it gets warmer runs smooth through the rpm but the idle stumbles I’ve had no luck finding any vacuum leaks replaced the spark plugs and O2 sensors and they were definitely old but didn’t look supper concerning maybe I’m missing something?
The new plugs and sensors didn’t change much other than it cranks over a little faster now I’ll have to check the plug wires in the dark to see if Mabey that’s the issue but they look undamaged in the light I can hear all the injectors clicking I’ve tested fuel pressure and it seems to have plenty of pressure and it holds it I checked the fuel pressure regulator and as far as I can tell no leaks fuel or vacuum I’m really hoping this isn’t an opti problem Mabey CPS or some other sensor that messes the idle up once in closed loop mode? I’m really not sure what to look for next any other tests I can do to rule things out as possible problems?
P0300 stumped
