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2005silverse

Dtc Po300

9 posts in this topic

hey guy i have this po300 misfire code that keeps coming back every couple of weeks or so the vulcan runs good ,i had this code along with a po316 which was part of a tsb for reflashing the ecu which i did about 2 weeks ago but now i only have this po300 code

i checked the normal things ,she is running well plenty of power ...im just not sure what to check ,plugs and wires are as old as the car is , the fuel pump is about a yr or so old , i use 89 octane fuel since i had it ,( about 3 yrs now ) just not sure what the next step is ,i had the fuel injectors cleaned about a mounth ago ,she is in top shape ,no maint needed at this time ,she only has about 52k on the clock ..........any ideas would be great .....now i have noticed that when this light comes on she is sitting out ,and fuel level is below a qtr tank .....and im using remote start .......she is normally in a garage and full would that cause a po300 code ? i cleared the code with no repairs yesterday to see what happens

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...im just not sure what to check ,plugs and wires are as old as the car is

Even with only 52k, the ignition system has seen 6 years of PA winters. P0300 is a generic misfire code. Remove the coil pack and check for hairline cracks in the plastic. Check all plug wire connections. Look for spark tracking on the plugs and inside the coil pack terminals.

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we had to replace the plugs on my moms 07 with about 60k on it the gaps were way out of spec. it was not misfiring though.

as Spridget said check the wires and the coil pack. it is possible that it is tracking. cold weather does not help either

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great guys thanks for the tip on the ignition coil ,we are kinda beat here at work with all the snow ,maybe ill check it out this afternoon

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on an '05, check what I call, the "resonance flap" on the back of the intake manifold on the side of the belts and accesories. it has a single plug on it ans is held in by 2 screws. There is a rubber gasket there, which usually starts to leak badly, giving the random P0300 code(s). I sprayed some starting fluid on the gasket mating area with the car running and immediately noticed change in engine behavior. I replaced this and the car has improved, but I still have a leak somewhere.

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i checked the coil ,on my lunch hr pulled it off and found odly enough a huge crack on the coil , called my guy at the ford dlr and said it was covered

so i took it over there hopefully thats the only problem w her

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here we are almost a year later and we are getting a po300 code again ,but i noticed i only get the code when its cold out and when using

remote start ,it came on last night ,i replaced the coil,all plugs and wires with oem parts last yr ,also a new fuel filter and i cleaned the injectors a month ago...

any suggestions on what else could be causing this issue ? the car runs great besides the light coming on

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Have you replaced the o ring on the variable valve actuator on the back side of the UIM. Common vacuum leak point.

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I have not done that yet , i just learned about this leak yester day and i do have that leak ,ordered the oring and a new cabin fitler yesterday ,hopefully this fixes it lol

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