P305 code

Welcome to 2CarPros.

Since the light is on and off, the first thing I would do is check freeze frame data to see what is happening when the light comes on. However, if you don't have a scanner which can do that, we will move on.

Next, when the light is on, do you feel a misfire? Are there any conditions which seem to cause the light to come on?

I am going to provide a list of things to check. See if it helps.

Inspect the engine for any of the following conditions:

- Worn serpentine belt

- Misalignment or binding water pump, P/S pump or A/C compressor pulleys

- Improper CKP, CMP, MAP, or TP Sensor mounting.

- Poor connector/terminal to component connection for CKP sensor, CMP sensor, MAP sensor, TP sensor, fuel injector, ignition coil, etc.

- Corroded PCM power or ground circuits.

- Vacuum leaks.

- Restriction in the air induction or exhaust system.

- Internal engine component malfunction.

NOTE: Misfire may occur and may not be caused by component failure. Any of the following conditions can cause a misfire:

- Moisture on ignition system components

- Insufficient fuel

- Low quality fuel

- Manual transmission bog

- Towing overload

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Now, just for the heck of it, switch cylinder five coil with cylinder one and see if the misfire changes cylinder. If it does, the coil is faulty.

Let me know if any of this helps or if you have other questions.

Take care,
Joe