cyberhiker

Hi Everyone:

In the midst of replacing spark plugs now. Haven't noticed any major issues but they've been in my '02 RX300 almost 10 years and 94,000 miles, so I figure it's about time. I've already swapped out the 3 fronts (I'm using the OEM Denso's) and plan to tackle the rear bank next. I've seen alot of talk on the board about coil problems from readers. How would I know I have a coil going bad? Do they always throw codes? Is there something I can check for now, especially while working on the PITA back bank, so I don't have to revisit them again later on?

Thank you.

Tom-

thomas1

It would throw codes.....When you do the plug change check the contact area very closely on the coil pack with a flashlight...make sure there is no corrosion. I had the coils in my 99RX for 12 years and never had a problem...As for the plugs, I would have left them till 125k miles...the iridium is awlsome, not like plugs of yesteryear.....

salimshah

Recommended replacement interval for spark plugs is 110k miles. Just as Thomas stated they can last longer (one of mine went bad at 145k).
There is absolutely no reason to change coil packs, unless they go bad. By the way shortly after I changed plugs, one of my coil pack went bad (could have been stressed by a bad plug).

The engine reports a misfire which can be due to bad plug or coil-pack.

Salim

cyberhiker

Thanks Thomas and Salim. Replacing the plugs now is one of those "while I'm here" things. I also just replaced the front O2 sensor. Had the usual CEL and the meter code indicating this was the bad sensor. It was also the only one left I to replace (did others previously). The front O2 sensor was THE WORST I had to remove. It just wouldn't budge. I ended up cutting off the sensor body and bought an Irwin 7/8" bolt extractor. What a awesome tool! (Ace Tools online) After tapping it on to the bolt base to set the teeth, I finally backed the snesor body out. Of course, I then had to buy an O2 sensor thread runner (Auto Zone) to re-cut the threads a bit in the manifold socket. But, happy ending. Dabbed on the anti-seize grease, threaded in the new sensor and the CEL's gone.

You get double the satisfaction with these DIY jobs: You know you've installed quality parts plus you've kept beaucoup $$$$ safe in your wallet. Once again, advice from this board played a big role!

Tom-