2000 ES with 279,000 miles. For about 2 weeks now, I’ve had an engine miss with no check engine light. The symptoms appear to be like a bad ignition coil. Two of the coils are still originals. Any ideas? Spark plugs are about a year old. Thanks.

 

See if you can pull any codes that are in a "pending" state.

 

Nothing is pending which is frustrating. Usually if it’s a coil, it will throw the code pretty quickly from my experience.

 

Hello,

Not exactly, depends on the severity, I've just recently had a case where the Coil was only partially dead, and would cause an occasional "hiccup" once or twice during the ride, but I never got any Codes for it. The issue was pretty easy to work out by watching the Misfire Monitors for each cylinder, during every "hiccup" one of the cylinders would get a Misfire, which would also move over to another cylinder when I swapped Coils around. Get a Scan Tool capable of reading Engine Live Data, see what you will get.

Hope this helps and best of luck!

 

I just got a pending code P0300 for random cylinder misfires. Hoping to get another code to help narrow it down.

 

If you had reason to change one ignition coil, that's usually good reason to change all of them. If only two are still original, that's where I'd look first. If it's intermittently happening on two cylinders, it might take a bit longer for the ECU to understand what's going on, hence the "random cylinder misfires".
Otherwise, it may be one of those annoying electrical issues. Have you checked the wiring to the coils?

 

Well in that case, the original suggestion in a previous post still stands, connect a Scan Tool capable of reading Engine Live Data, if you will see the two Cylinders in question Misfire, and if the Misfire will move to different Cylinders if Coils are switched around, you will know that it's time to replace the Coils. That way you will pay for new Coils only if you have to.

Hope this helps and best of luck!

 

Yes, the wiring looks good. I will try to get a Scan tool and hopefully see where the misfires are happening. Thanks!

 

Update: Got a flashing check engine light. Plugged in my scanner and got a P0304. The misfire and hesitation was due to this ignition coil. Put one of my 25 year old coils and the hesitation went away. I will swap out the faulty coil.

 

Getting 279,000 miles out of an ignition coil is excellent.

 

I have all of the coils replaced with some from Oreilys. Not the best quality as seen on the attachment, but you get a lifetime warranty.
🤷🏻. I’ll keep 2 good originals just in case one fails on me.