M45owner

Last week we experienced a misfire with out RX300...it randomly happened out of nowhere and the check engine light was flashing while driving which indicates that it was misfiring at the time of flashing.

Codes were for 2 of the coils being bad...cylinders 2 and 4. So we replaced all of the spark plugs and moved the two bad coils to the front in case they needed replaced. Sure enough once the car was started, it threw codes for cylinders 1 and 3. Replaced both coils and it ran just fine with no CEL. Rrove the car around Saturday through Monday with no issues.

Fast forward to today, Tuesday and all of a sudden the car starts sputtering and misfiring again. Had codes checked and they were for cylinders 2-6....but not cylinder 1. Drove home and the car drove fine...then had a hiccup a few times on the way to the shop. Pulled the codes and sure enough 2-5 bad ignitors.

They didnt know what to suggest so I drove to Lexus thinking surely they would figure it out. I wait an hour and all they say is they dont know whats wrong other than its throwing codes for all coils being bad. Thanks a lot, worthless *******s. Told me to bring it back when it gets worse. WTF!?

So here we are, replaced 2 coils with new ones from O'Reillys and even those ones are coming up as bad when they were working just fine the past 3 days. And all or a sudden every single other coil is bad??? I dont think so.

I dont want to buy all new coils just to have this same thing happen, as we replaced the 2 and those 2 come up as bad now also. Where should we look for the problem? Any ideas?

M45owner

Nobody????

salimshah

What you are experiencing is bizarre so that is why it is hard to diagnose.

It may be late, but please make sure you are using OEM coil packs and OEM spark plugs (NGK - Irridium). RX are finicky and you dont want to throw in unknown variables. Also the work has to be done with utmost care as pinched wires and weak connections give you random defects.

What was done to the vehicle before the problems showed up?

There is too much in description ... so in summary ... if you have a problem with all cylinders then timing belt or crank-shaft position sensor comes to mind. If they are bank related then something related to bank sensor comes to mind and if both banks are involved one has to think about potentially both the vvtis can be bad (unlikely but it can happen).

I would suggest a revisit to the dealer (or another dealer) or going to Toyota dealer or an indi who specializes in Japanese imports. You need an advanced reader to analyze what is going on.


Salim

metah2004

Replace all 6 coils with factory coils do not use aftermarket they will give you nothing but problems trust me

carguy07

What spark plugs did you put in it?

manianac

Toyota MDT here, you want OEM coils, no exceptions. And make sure you got NGK or Denso plugs, no Bosch or other non-sense.

M45owner

Thanks for the replies....we dropped it off at the dealer AGAIN Monday morning. They said they would call us later that day or "tomorrow" (Tuesday) with what is wrong. Well, they called today saying they were STILL working on trying to figure out the problem. 3 days and the Lexus dealership doesn't even know what is going on!?

The transmission went out roughly 350 miles after we got the car...had it replaced AT LEXUS. Did the timing belt and water pump job at the same time. No other issues until 2 weeks ago when we got a misfire on 2 cylinders...I believe it was 1 and 3. Moved the "bad" coils to the front of the motor and changed all spark plugs with NGK Iridium plugs. I never use the Bosch or any other garbage in my cars.

Now cylinders 2 and 4 were showing the bad coils, which is where I put them. Put in new coils and it didn't throw any codes and drove like a top until Tuesday (we finished the work on a Saturday)...so 3 days it drove fine. Tuesday we started experiencing the misfire again except it was on EVERY cylinder EXCEPT cylinder 1. Drove like absolute ****.

Took it to a local shop, they didn't know...took it to Lexus, they didn't know. Told me "it has to get worse so we can find out the issue". Well, it never got better and it still misfired even more afterwards. So we just dropped it off again this past Monday morning.

Codes are P1305, P1310, P1315, P1320, P1325....all "igniter circuit malfunction" for cylinders 2-6. No other codes present.

salimshah

Hang in there buddy. Some problems are easy and some are hard.

Salim

M45owner

Dealership still has it....7 days now. "Can't find the issue"

salimshah

Ask service manager if they are in touch with regional or national mechanics.

Salim

Bobster999

anything yet?

DeadRX

anything? car's in shop now waiting to have codes read. *****ing my pants.

PeglegGold

? I have a 1999 Lexus RX300, 200,000 miles. Check engine light on, Diag brings up O2 sensor. replace 02sensor, still the same misfire. Diag, O2 sensor. Replace second 02 sensor, still same misfire. Check engine light back on, diag now engine coil. did this 3 times. Replaced 3 engine coils,replaced spark plugs. Still the same misfire with check engine light on, now will not go into overdrive. Reset battery, goes into overdrive now, next check engine light back on. Same diag, engine coil. Now head lights start streaming brighter than lower, same with check engine light on dash, Gets brighter than lower, also some times my cruise does not work until I reset at battery. Than my speedometer not working until I reset at battery, will not go into overdrive now until I reset at battery, sometimes when I reset at the battery, it will run fine. Checked the Oil Control Valve, it was fine Than we start all over again, now it never runs smooth, always like it is running on 5 cyl (it is a 6 cyl). All this to me sounds like a computer to me? What do you think?

JAB

Alternator and/or battery may be dying.

carguy07

Post the codes you are getting. Are you replacing with OE/Denso parts or aftermarket?