Random Misfire

[Springer]

HELLO

I'm a first time poster with this forum. I bought a IS300 last year,2004 automatic nice little rocket!

As I work away a lot the car was parked for a couple of weeks before I had a chance to have some fun with it. As soon as I started to drive it a little harder it coded up P0300,P0303&p0304 random misfire on cylinders 3&4. I'm a helicopter mech. so I purchased a good quality code reader and proceeded to try and figure out the problem. I changed plugs first, no change,swapped coils all locations 2 times and wires were changed , still no change. Removed intake and swapped injectors, it still codes the same.

This leads me to believe that I have a faulty ECU, has anyone had this problem or something similar

any info would be appreciated.

Thanks Richard

[James Horning]

Check your fuel quality, smell it, compare it to another car.

Water ( from engine washing or condensation ) is common in the spark plug tubes as well as oil is that has leaked out from the spark plug tube seals.

Poor fuel no. 1.

Code readers do nothing unless you under stand criteria of the code, if I have a data list, I need no codes .

Fuel will not show up in anything.