My yellow ingine light is on, i've lost power , my

Change the coils.

A flashing Check Engine light means you have a ignition Misfire, start by replacing the spark plugs and spark plug wires, one or more is defective. If you have a electronic engine control fault code reader the cylinder or cylinders that are misfiring will set a fault code, the codes are P0300-P0306, the last number being the number of the cylinder ( cylinders 1-6) the computer has detected a misfire in.

One thing you didn't say you replaced was the plug wire. That could also be the problem.

Sounds like you may have a misfire. Scanning the computer for codes will help you narrow down the possibilities. If it is a misfire you will see a code or codes similar to P0301 thru P0306 which are specific cylinder misfire codes. P0301 being cylinder number 1, P0302 being cylinder number 2, etc. You can then focus on those cylinders to see whether they are getting spark or the condition of the spark plugs.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

have the system tested for fault codes, i think u will find that u have a misfiring cylinder

yes if 1 and 4 are on the same coil pack, thats the place to start and i think thats your answer

Code P0301
Ignition Coil Pack
Ignition Cable
Spark plug
Clog or dirty fuel injector
Evap canister purge valve
Engine Compression
fuel pressure

you have 3 type of engine for your truck
2.3L 4 cylinder
3.0L 6 Cylinder
4.0L 6 Cylinder

need to know that type Engine

The reason why the service light come on because it is a hard code
not a soft code.

Let me know

I somewhat agree with other solutions on this page. I agree that what you are describing is a severe misfire, however there are MANY possible causes for a severe misfire other than just the spark plugs...I recommend diagnosing the CAUSE of the misfire before spending any money "GUESSING" and replacing a bunch of parts.

Also, a code P0300 is a "RANDOM MISFIRE" code which indicates that there is definately more than one cylinder misfiring. Your computer MAY display this code, however, a SINGLE cylinder misfire can also cause a loss of power and the check engine light to flash.
You may just have something like a bad coil on one cylinder that needs to be replaced. This is why PROPER diagnosis is recommended.

check the wiring connector going to the coil pack. you will probably find one wire corroded going into the connector. Ford sells a connector kit for this repair @ $35..
It will turn on you check engine light. Is it on?
Let us know outocme

Have a code test run to ind out which cylinder is the problem, then check the plug wire boot at the spark plug to that cylinder, I think you will find it is burned through and shorting the plug wire to the cylinder head.