Engine Missing and Check Engine Light On

Hey Austin, I have a Ford Expedition and the engine is missing and the check engine light is coming on. I replaced the spark plugs, but that did not solve the problem. Could it be a fuel pump or sensor problem?
Thank you sir,
Janice

Hi Janice,

First thing to do would be to read your on board computer codes with a hand scanner to troubleshoot the problem. Chances are you do not have a scan tool, so I would test your spark plug coils first before I did anything else.

With the engine OFF unplug the first spark plug coil connector, start the engine and see if the problem is WORSE than before. If it is, shut off the engine and reconnect the coil connector and unplug the next coil in line and start the engine. Repeat this process until you find the coil that when unplugged is producing the same engine miss as before.

You are trying to find which coil is bad, and if the coil is not working when it is plugged in it will not affect the running condition (make it any worse than it already is) when it is unplugged. The engine might not start at all if a good coil is unplugged, so if the engine has trouble starting with the coil unplugged, you can assume that coil is working properly.

Here is a picture of a spark plug coil, and the middle one in the picture…the clean one is a new one. I have seen many coils fail around the 60,000 mile mark. The coil supplies the power/spark to the spark plug. If the coil fails the spark plug stops working…thus an engine misfire occurs.

Andi birthday 044

Blessings,

Austin C. Davis

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Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."