P0305 Ford F150: Comprehensive Guide to Diagnosing & Fixing This Common Problem

Hello, my name is Aaron Marcus and today we have a 2006 Ford Explorer in the shop with a V8 engine. The customer has reported a bucking and jerking under a load at speeds below 45-50 miles per hour, especially when going uphill. Additionally, the check engine light is on. It sounds like a misfire, but we need to diagnose the issue to be sure.

First, we checked the engine codes and found a P0305 code, indicating a cylinder 5 misfire, and a cylinder head over temperature code. According to the diagnostic chart from Ford, we needed to address the misfire first as it could cause the PCM to set the over-temperature code.

We inspected the cylinder 5 coil pack and noticed moisture damage, likely caused by an intake leak. The damaged coil pack needed replacement, and we also confirmed that the intake gasket had been previously replaced, ruling out any intake-related issues.

After replacing the coil pack, we cleared the codes and test drove the vehicle under load to confirm the misfire was resolved. It’s important to test the vehicle under load as that’s when an ignition misfire is most likely to occur.

Ultimately, replacing the entire coil pack assembly resolved the misfire, and we confirmed that the issue was fixed by test driving the vehicle again.

It’s essential to note that attempting to clean or replace just the boot of the coil pack often leads to failure, as the entire assembly needs to be replaced to ensure a lasting fix.

What are the symptoms of the 2006 Ford Explorer with v8 engine?

The customer is complaining of under a load under 45-50 miles an hour like up a hill, there’s plenty of bucking and jerking. Also, the check engine light is on.

What were the diagnostic trouble codes found?

The codes found were a p0 305 (cylinder 5 misfire detected) and a cylinder head over temperature detected (p1 285).

How was the misfire diagnosed?

The misfire code (p0 305) could cause the PCM to set the p1 285 over temp code. The cylinder 5 cold pack was checked and found to have moisture damage, indicating the need for replacement.

What was the suggested solution for the misfire issue?

The entire cold pack assembly for cylinder 5 needed to be replaced. Aftermarket BorgWarner cold packs were recommended.

After replacing the cold pack, what was the next step?

The codes were cleared, and the vehicle was taken for a drive to confirm that the misfire was gone and to check if any codes reappeared.

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