codes P0354, P0355, and P0357, check engine light?

2004 MERCURY GRAND MARQUIS
247,250 MILES • 4.6L • V8 • 2WD • AUTOMATIC
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PETPARENT
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Car has the codes P0354, P0355, and code P0357. Before it had P1336 and P0128 as well as 0355 and p0357. The car had blown out coil pack #4. I re-tapped cylinder 4 and put in a new plug spark plug insert and coil pack, also i put in a new thermostat because of code P0128. Because of the codes i had a mobile mechanic confirm my first code read.
Jan 27, 2025 at 2:33 PM
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JACOBANDNICKOLAS
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The codes you have are all related to ignition coils. Have you tried moving them around to see if the codes change? Are you experiencing misfires while the engine is running?

Also, confirm the PCM connectors are tight, clean, and dry. The PCM is located under the hood next to the power brake booster. See pic below

Let me know as much as you can.

Joe

See pic below.
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Jan 27, 2025 at 7:27 PM
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PETPARENT
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What I meant to say is that the mobile mechanic relearned or reflash the computer in my car? Ignition coils are all new. You think that I should move them around before I try the new crank position sensor and?
Jan 28, 2025 at 7:42 AM
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JACOBANDNICKOLAS
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Hi,

If all coils are replaced, I don't think that would be the issue. It could be related to the drivers in the PCM, but the only way to confirm is to perform diagnostics.

If you look below, I attached the diagnostics for P0354, 355, and 357. The codes all take me to diagnostics JF1 in the manual, which I attached below.

Take a look through them and let me know if you are comfortable performing them.

Take care,

Joe

See pics below.
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Jan 29, 2025 at 7:19 PM
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PETPARENT
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Yes the answer was helpful. i will try the to diagnose the problem using your flow chart.
Feb 1, 2025 at 12:09 PM
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STRAILER
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Also, I would clear the codes, then start the engine for about 5 seconds and then run the codes again, this will give us the most relevant code to fix first, also, I would check the spark plugs, I have seen a spark plug get cracked and cause these codes.
Feb 4, 2025 at 8:38 AM