I have a 2007 RX 350 with 169,000 miles. Lately I've had three occasions of my Check Engine Light starting to flash, followed by sluggishness/misfiring. Had diagnostics checked 4 days ago (figuring it was a coil and praying it would be one of the coils that are easy to get to). When my mechanic looked at the results it showed all 6 coils were failing. He was confused by this and said it was strange to have all six showing a bad code so he cleared the codes and told me to bring it back in next time it's misfiring/showing a flashing check engine light and he'd hopefully be able to narrow done a specific coil. I'm wondering if anyone has had a similar situation? Any advice?

 

6 coils don't go bad at once. What brand are they? Have yu or the previous owner ever had the coils replaced? Aftermarket coils are notoriously bad but even bad ones wouldn't all go at once. Sounds like your mechanic is happy to spend your money without doing a comprehensive test to find the actual issue he'd rather you spend a bunch on his labor "hoping" replacing random parts temporarily solves your problem. Go to an Autozone or O'reilly's have them run the codes in the parking lot report back what you find as there will be codes stored in the car computer. People have had similar issues but you want certain answers not what an anecdotal person experienced.

As usual you need to give us FAR more details:
When was your last maintenance and what did they do?
Any symptoms prior?
Did you do anything at all difference just before you epxerienced the syptoms? Tried a differetn gas station? Have the car parked for extended period of time? Any chance you have mce or rats near the car?

 

I don't know the brand of coils and don't believe the previous owner had replaced them. I apologize for lack of details, I'm not really a "car guy" just thought I'd get a little advice from people with more knowledge than me! Recent maintenance I've had done- new oil coolant lines, new valve covers, new water pump, new alternator & battery. No symptoms prior and just my typical driving before this started happening. I only use two gas stations, has not been parked for an extended period of time and no mice or rats near my car. Autozone/O'Reilly's are over an hour drive away, but I'll have to try make it there sometime soon. Thanks for any advice!

 

that helps a lot, no worries not being a car guy we all start someplace or have our strengths. Might you know ayone taht is a car guy who might have a code reader? They are cheap and can be had for maybe $40 or less so many people have them also as mentioned most auto parts stores have them to borrow so you might call an local auto aprts stores to see if they've got one. Are you friends with any garages or other mechanics perhaps? The code reader is either a thing the size of your phone with a cable that plugs in under the left side of your steering wheel or some are just a "dongle" that plugs in and you read it on your phone or computer it gives codes from the cars computer telling us what the issue is. For the record - aftermarket coils are bad to use but often people do because they're cheap however I do not believe that all 6 of yours went bad that doesn't happen only one at a time. Good luck, report back.
Being it is not mice or rats it is not likely your wires being chewed up from the car sitting
Doesn't sound slike a bad batch of gas.

Is the car running OK now? You may want to run it fairly hard, keep it ina lower gear and get teh car to rev up high for maybe 30-60 secs.... if you have a long hill to climb nearby that would put a load on the car which is even better as engines need to clear out every so often running them constantly at low RPM's builds up carbon over time it is good to run them up every so often.

 

If you want to DIY on your car you NEED your own code reader.

Please read leepers posts above.

Also, please pull your coils and i inspect the tubes for cracks and burn marks.

All it takes is for one coil to fail in a "rare and special way" to get an all 6 cylinder misfire

Reason why is because all the coils share a common "feedback" wire that lets the Engine Ecm know that the coil has fired, one after another.

An internally shorted coil can make the Engine Ecm think all cylinders are misfiring when you only actually have one smoked coil. Haha

Happened to me- pull your coils and look for damage, burnt marks, and cracks in the tube.

Hopefully the damaged coil will be obvious.

ALSO, we have two types of misfire codes on our cars and this is why you NEED your own scanner.

One type is specifically for the coils and the other type is for a "generic misfire", which could be anything. Lol

Another thing that comes to mind is a damaged or faulty "crankshaft sensor"- need an oscilloscope to scan that sensor or a proper tech. Lol

 

A basic bluetooth OBD2 code scanner can be found on Amazon for less than $30. They all work similarly below that price, just pick one with good recent reviews. I use mine with the carscanner.info app and it works well for checking OBD2 codes and several other things.
I do remember having a bit of difficulty getting it configured for the RX ,but once you figure out how to pair it with your phone and set up your car in the app, it works well.
Also, my first thread here was diagnosing a similar issue, so it may help you:
https://www.clublexus.com/forums/rx-...tion-coil.html
I had another coil fail in the mountains two years ago too. Fortunately it was in the front and I had a spare (I started keeping extras in the car.) and just stopped and changed it. No further issues.