2007 Ford F150 4.2l V6. While driving tonight my engine started shaking and I eventually noticed a slashing CEL. I slowed down and at times it went away only to come back if I sped up. I got to where I was going and it sat for 5 hours. Drove it home and the same thing. On the way home I noticed if the engine shook this CEL would flash but if I kept it under 40 it would hold on a solid CEL. Again if I crept up much past 45 the engine would shake and the CEL would flash. Keep it to 40 or below and a solid CEL and a fairly smooth ride. Several people told me different things. I am in no way a mechanic and know nothing about engines. I was told maybe spark plug(s) went bad or something called coils may be bad. I'm just looking for thoughts as I have no idea what to do. Thank you in advance.

 

You need to connect a scanner to read the code(s) present.Any of the large auto parts stores will do this for free. Then I would leave and do some diagnosing before buying any parts.The advice you have been given is just guessing.

 

Most common issues for your symptoms are spark plugs, and or coils. How many miles on the beast?
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^i agree. those are the most common symptoms