Cel 0300 Random Misfire

[crazyinjungirl]

I am not mechanical but i am interested in gaining a bit of knowledge before driving into the shop with my 2000 RX300. It began running rough this morning and the CEL began blinking shortly after. i had the codes read at lunch today and it was the "random misfire" misfire codes for 1,2,3 cylinders etc. ...there were 6 codes in total, the guy who read the codes did not let me really look at them, he just said "all the cylinders and the 0300 code was what was coming through"

i want to know, in the order of cheapest first...what should i attempt to fix....fuel filter, spark plugs? etc....any info would be graciously accepted.

[tmastres]

this post sounds very similar to your problem

http://us.lexusownersclub.com/forums/index...hl=coil+replace

Assuming it is a bad coil, You may need to have the codes read again and generally its the first code that tells you which coil is bad. Once you've driven the car on only 5 cylinders (because one isn't firing due to the bad coil) you'll get a bunch of other codes that will go away once the mis-fire is fixed. If you're lucky the misfire will be in the 2,4 or 6 cylinders which are right up front and the coils there can be changed in less time than it takes to change a tire.If its the 1, 3 or 5 you'd better budget a few hours. The replacement coils cost anywhere from $75-$110 depending on where you get them. Be sure you get the #90080-19016 as these are re-designed coils that fixed the problem which caused the original ones to fail.

Lastly and this will be painful, but assuming its the coils, I would bite the bullet get all 6 coils changed to the new versions. These coil failures are totally random and in my experience absolutely unpredictable. I had three coils fail in a 15 month period before I finally went "DOH!" and changed the remaining 3. I was super lucky that the three times they failed I was close to home and could either limp the car home or simply swap out the coil in the parking lot (after 2 failures I carried a spare coil). Point is if one fails more will follow and you don't know where you'll be when it happens.