1999 Pontiac Sunfire PO200 & PO300 codes

FREMONT

MEMBER
1999 PONTIAC SUNFIRE
160,000 MILES

Looked at almost everything that relates to these codes and I can't find anything wrong but I got a bad miss. What is the chance I got a bad PCM? GOOD wires, plugs, coils, ICM, New crank sensor, Cam Senor? Did unplug and did get code, so I believe it is good? Injectors are good, I did a noid check on all 4 and that looked good. High speed runs good, low speeds and idle a real bad miss?

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JACOBANDNICKOLAS

MECHANIC
109,644 POSTS

Are you able to narrow it down to which cylinder is missing?

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Saturday, July 13th, 2013 AT 9:01 PM

FREMONT

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No I am not able to, it is so random. The spark plugs #3 & #4 were blackened(rich) #3 was more then #4. #1 & #2 looked good.I also hooked up my test light to see witch cylinder is missing and they all are. The car starts up with no problem. I tried a leak down by pulling sprk plug wires and it so hard to see a difference? I thought a about a compression test? The car has been running fine, so something went out just like that?

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Sunday, July 14th, 2013 AT 12:01 PM

FREMONT

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One other thing. I need to make up a fitting so I can check the fuel preasure. Do know if they sell that fitting/tool to hook up my fuel gauge tester? I will look on line for one. This is one thing I havent checked. I can hear it run when I turn the key I just don't know the PSI?

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Sunday, July 14th, 2013 AT 12:06 PM

JACOBANDNICKOLAS