Spark plugs - 2007 Lexus ES 350

lexus
es350

#1

I’ve had the car since new and this just started happening 3 years ago. I would get the VSC, anti-slip and engine light and the car I could feel was misfiring. But what I did notive is that i was getting 560 miles per tank wersus 430… WOW I didn’t want to correct it but I knew the engine wasn’t right. I changed to plugs and a coil here or there from the auto zone diagnostics tool-3 of the sparks posts were gone, I didn’t use the iridium. But I’ve gone through this 3 times now. It has to be something sending the voltage to the sparks. What do I need to look at, besides getting the shop to charge me 3 checks?


#2

I suggest using ONLY the exact spark plugs listed in the owner’s manual

Either go to the Lexus dealer, or have a shop order the correct ones for you

Don’t let auto zone talk you into buying the ones they have in stock . . . UNLESS those are exactly the ones listed in the owner’s manual

How many miles . . . ?

any of the spark plug boots visibly damaged?

coil(s) visibly damaged?

you did replace the plenum gaskets when you replaced the plugs the first time, I hope . . . ?!


#3

I’ll check with the oem, i do replace the plenum gasket. I’ve got 260k miles on this and i want to drive it till it stops working. The spark comes were changed 6 months ago, though this time i didn’t use oem. I figure if i go to the parts store and read the code it will be another spark plug. I was wondering if it was a device sending the voltage erraticly.


#4

Coil failures are seen more on the 2007-2008 ES350 and RX350 than any other year. What were the fault codes from your ECU?


#5

Could it be the cat converters clogging?


#6

If you are referring to the top of the spark plug that the boot or coil-pack plugs onto, if that part is being damaged or destroyed by running the engine, make sure the electrical contact there is good. If it isn’t a good electrical contact the spark will occur there and at the tip of the spark plug, which could explain both the misfiring (from a weak spark) and the damaged spark plugs.


#7

The damage was at the post under the arc. I had an alternate plug then and that’s when i noticed my mileage was great. I just got the ecu read and our shows po304 only


#8

P0304 is a misfire on cylinder number 4. Upon removal does the number 4 spark plug look different than the other three?


#9

Suggest taking a close look at coil #4 . . . is it cracked?

Might not be a bad idea to perform a compression test on #4 cylinder

If there’s low compression, best to know now, versus throwing lots more money at the problem . . .