Computer Code PO300
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No CEL Light.
Tom,
Often the P0300 error will not give you a CEL light. which brings up the question does it need to be fixed. In you case, a short ruff idle when cold it may not be a big issue. You may see a slight improvement in gas millage if its fixed. Your choice.
Dave
Often the P0300 error will not give you a CEL light. which brings up the question does it need to be fixed. In you case, a short ruff idle when cold it may not be a big issue. You may see a slight improvement in gas millage if its fixed. Your choice.
Dave
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Joined: Nov 2003
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My son replaced the plugs and wires about 8,000 miles ago, with no problems at all during that time. Then about 1,000 miles ago, the "check engine" light came on and stayed on. I rechecked the wires and checked for vacuum leaks, and found nothing wrong. AutoZone ran the codes and we first got a code P0300, which is a "random multiple misfire". Not much to go on. They reset the computer and a couple weeks later the "check engine" light came on again. A code P0303, "plug 3 misfire" popped out of the computer. I checked plug 3 and found nothing wrong. The weird thing is that this afternoon the "check engine" light went out, and has not come on again after about 50 miles of driving.
My son-in-law, a Ford mechanic, had previously told me to run some injector cleaner through the engine because he thought the number 3 injector was clogged. Turned out he was right. I ran Lucas injector cleaner through three tanks of gas and the "check engine" light mysteriously went out this afternoon. This may be of help to you if your "check engine" light comes on again and you get a code P0303.
My son-in-law, a Ford mechanic, had previously told me to run some injector cleaner through the engine because he thought the number 3 injector was clogged. Turned out he was right. I ran Lucas injector cleaner through three tanks of gas and the "check engine" light mysteriously went out this afternoon. This may be of help to you if your "check engine" light comes on again and you get a code P0303.
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