jayco5

Hello CL (my first post),

I've had my 2000 ES300 for about 3 years now and I've put just over 60k miles on it - for a total of 105k. No problems until today when all of a sudden it was vibrating, idling slow, and running strangely. I thought it was just missing on one cylinder, but the touble code says P0300 - multiple misfire, and it also says misfire on cylinders 1,3, & 4. So far, we've inspected the front spark plugs, the crankshaft position sensor, and the front bank camshaft position sensor - but nothing seems out of whack. We then reset the computer by just unplugging the negative battery cable and drove around until the CEL came back - same trouble codes - P0300 & misfire on 1,3, & 4. I'm looking for ideas/help or a method of narrowing down the possible culprits. Since it happened all of a sudden, I just can't imagine that multiple plugs or coils went bad simultaneously.

Any help is greatly appreciated.

~Justin
2000 ES300 - 105k miles
No aftermarket - no past major problems or accidents (that I know of)
I have used Seafoam about 3 or 4 months ago.

intrmsof2

Start by determining if all 6 cylinders have spark, then check to make sure all six are recieving fuel. If the ignition and injectors check out, try a compression test. Two of your three problem cylinders are right in front and easy to access, so you should be able to get a good idea of compression without disassembling too much

Other easier checks that can throw things off:

Engine Coolant Temp. (ECT) Sensor
Mass Airflow (MAF) Sensor

A malfunction in either can cause the computer to change the air-fuel mix, which can also cause a misfire.

Good luck, hope you get it worked out.