My wife's '99 RX300 got very sluggish yesterday and the CEL started blinking. My scanner showed code P0304 (cylinder 4 misfire), so it is probably the spark plug and/or the coil wire. My dealer is 140 miles away and cannot get to it for 5 days, and I have had unfortunate results with local mechanics (don't even mention Toyota to me), so I WILL take it to the dealer.
My real question is: is it OK to drive the car around town? to the dealer 140 miles away? What damage might be done if I keep driving it? And why is the CEL blinking instead of being on steady? I'm very
Thanks in advance for any help or suggestions.

 

Well John, the code you listed is a "misfire" code, the ECM in the RX uses the crankshaft position sensor and the camshaft position sensor to monitor changes in the crankshaft rotation for each cylinder. If the misfire rate is high enough and the driving conditions will cause catalyst overheating, the CEL blinks when misfires occur. I would think the only real thing that I would be concerned with is that the catalyst can overheat with this condition. I know it is not great for the engine, but it depends really on how much the CEL light blinks. I would call the Lexus dealer you are taking it to and see about a loaner car or something and leave it with them since it will be a number of days before they can address the concern.

 

John,I would not drive it.Fist off a blinking cel is not good.2nd,it sounds like you lost a coil on that cylinder,and as smerre mentioned,the very least damage will be your converters from unburned fuel.

 

You know you could probably fix that one real easy. Chances are the coil is bad, and if the code is p304 that is the middle spark plug on the front of the engine which takes a whole 5 minutes to get to. Buy the coil pack or swap it with either the coil pack on the plug to the left or right of that middle plug and see if the code changes. If it does than that coil pack is bad. Replace that middle coil pack that you moved and you are fixed. The plugs are pretty good if they are the originals. Dont suspect the plug is bad. I wouldnt drive it a lot as you might be throwing raw fuel to the catalytic converter when it missfires.
here is a little tuturol on how to get to those plugs and coils...
http://vishesh.narayen.com/?page_id=90
You can do it....by the way the coil packs cost around $60 to $80 depending on where you get them....

 

If you have a Toyota dealer (you don't need to take it to them for service), you can pick up a V6 Highlander Ignition coil for the 2001-2003 model years and that will work. This is actually quite a simple DIY (as opposed to if you had a misfire on the rear plugs/coils). I had a misfire myself back in Dec. 2005 on the way to the track and we eventually had to smooth down a Camry coil (no Highlanders in Mexico), but that did the trick until I could get a true coil for my RX.

Personally, I wouldn't drive after I had gotten it to a safe place. What is talked about above by my colleagues is absolutely true and my uncle and I saw at least 2 disasters, one of which occurred with a Renault Clio company car (first week I went to work) that my uncle wound up fixing, because nobody paid attention to the CEL nor other issues until it was to late (cat fried along with an A/F sensor).

 

Every one here summed it up pretty good. Don't drive it like that or you'll end up with more than just a bad coil.