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Misfire under load 99 4.6

Hello All,

I have a 99 Expedition 4.6L 73,000. I've been experiencing misfires under load. Most usually around 45 to 50 mph 1400 rpm. If the truck needs a little oomph to go up an incline the engine will seem to misfire until I hit the accelerator and it shifts out of overdrive and the rpm's increase, and the engine runs easier.

From what I've read so far it could be bad coil packs, wires, plugs, etc. My question is, If I need a coil pack, is there a preferred brand other that a standard replacement from say napa, autozone, etc? I guess the same goes for plugs and wires.

Has anyone ever reliably kicked this issue the first time around, or is it hit and miss. The first step is hoping my mechanic has the obd tool to get the codes. If not it looks like I have to see the dealer...$$$$$$$.

Either reply to the group or remove nospam from my email address.

Thanks,

Brian

Reply to
n3lka
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Why don't you start by changing the plugs and the fuel filter. Then use troubleshooting techniques to check out the other components (check for arcing in the dark, check the resistance readings of the coil and wires, etc.).

Reply to
andro

Thanks, I just changed the fuel filter, the weather is here is kind is still kind of cold to change the plugs and everything else. I was going to buy a code scanner and then see where the miss is, and try to swap the packs and see if the problem moves.

I like the idea of checking for spark in the dark. I'll give that a shot. I've seen cheap code scanners for about $29.95. That should give me a start.

Thanks,

Brian

Reply to
n3lka

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