Intermittent rough idle with flashing check engine light?

Hi,

The flashing check engine light indicates the engine is misfiring. When was the last time the engine was tuned up?

As far as the blue smoke, oftentimes failing valve seals are the cause. They allow oil to bypass them while sitting. When the engine is first started, the oil burns off and then stops.

Here is what I suggest. Scan the computer to see if there are any diagnostic trouble codes. I suspect there will be related to the misfire. The scan will identify which cylinder is causing the misfire so we can check if the spark plug for evidence of oil issues.

Here is a link that shows how to scan all modules (CAN-scan):

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

If you don't have a scan tool, most parts stores will scan the computer free of charge.

Make sure to write down the code and let me know what you find.

Take care,

Joe

I appreciate you getting back to me and what I've found was cylinder 8 misfire. Codes P0018 and P0308.

Hi,

The P0308 does indicate a misfire on cylinder 8. What to do is this. Switch the coil pack on cylinder 8 with a different one on the engine. See if the misfire changes cylinders. If it does, replace the coil.

Next, the P0018 is related to a camshaft timing issue. Is the engine oil clean and full? Has it been changed on a regular basis?

Let me know.

joe

I will try switching the coil pack tomorrow. As for the oil, the truck is definitely due for an oil change.

Hi,

Try the coil switch and let me know. If possible, when you remove the number 8 coil pack, see if you can get the spark plug out to inspect it. Be careful when you do this. They are known to break or damage the threaded portion of the cylinder head.

Change the oil as well. The variable valve timing is controlled by engine oil pressure. If there are any restrictions due to dirt and debris, it can cause this to happen.

Once you change the oil, drive it for a few miles and check the condition of the oil. If it appears dirty again, change it again. There is a detergent in the engine oil that will help clean away dirt and deposits. If changing it twice doesn't help, then we need to check for issues with the VVT solenoid and a few other components. Pay attention if there is any noise from the front of the engine.

Let me know what you find.

Take care,

Joe

Thanks.

Hi,

You are very welcome. Let me know how things work out or if I can help in any way.

Take care and enjoy the remainder of the weekend. LOL

Joe