Tune up and cel code questions


Jul 10, 2008
Hey guys, since I'm no Mustang expert I figured I'd defer to the experts. I have a friend with a 00 Mustang GT that has a couple CELs and needs a tune up and wanted to ask you guys what you recommend.

As I stated, it's a 2000 model but about a month ago, her timing chain went and was told she needed to buy a new timing chain kit. Turns out, when it went, it took a good bit of material with it. It trashed some of the chambers in one of the heads, took the oil pump with it, etc. So her friend had a wrecked 97 GT and she had him swap the engine out of it to put in hers, along with the new timing chain kit she had purchased already. She's been driving it since but has mentioned she has some CELs, and the low coolant light stays on. She said the misfiring makes her hesitant to take it on longer drives and her fuel mileage is starting to suffer. She doesn't know if he did plugs and a basic tune up while he had the car or not.

She is getting a P0306, a pending fault for C1501 (whatever a chassis code is), and a pending P0455. So with the misfire, I plan on getting some new plugs and installing those and cleaning the connectors on all the coil packs and seeing if that clears up the misfire before I swap a coil from another cylinder onto #6 to see if the misfire follows the coilpack or if it stays on #6. For the P0455, I'll get a new gas cap and check the area around the fill neck for any potential worn rubber or holes in the fill neck and check out as many vacuum lines as I can find. If that doesn't yield any results, I'll check further into that one.

As far as the plugs go, what do you guys like to have them gapped at? When I was checking various brands on Rock Auto yesterday, there were multiple brands that stated they came pregapped to specific clearances. I've always had good luck with NGK in my imports and domestics but if there is a plug with a proper pregap, I'll order those.

Are there any issues related to swapping the older 97 motor into the 00? Maybe the newer models used different sensors that would potentially cause issues, or is everything on the motors the same so it's plug and play?

I did read yesterday that it is quite common for the coolant low light to come on due to what is likely a worn out sensor in the reservoir, but for good measure, I want to flush out as much of the coolant as I can and put in fresh 50/50 mix with distilled water, and flush out the heater core some too. That way, it's prepared for when fall/winter roll around. I don't know if the guy used a garden hose to fill it, if it has any coolant in it and is mostly just water or what.

What are your opinions on the Denso, Delphi, or NGK coilpacks? They're about $10 cheaper than the Motorcraft and one of those is likely the manufacturer or the Motorcraft anyways. I've always been told by mechanics I trust that when replacing coilpacks, replace them all at once or they will eventually start to fail and you'll be in the same boat you were before; so that'd be an $80 savings.
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