P0301 and p0300. Lost. ECM?
 

1998 Toyota Camry. 3.0 v6. 263,000 miles, but engine rebuilt 80,000 ago by certified Toyota dealer. Engine code p0301 (cylinder one misfire) and p0300 (multiple cylinder misfire). Have changed plugs, boots, coils, wires, egr valve. Cleaned Intake air sensor. Cleaned map sensor. Problem is intermittent. Usually occurs after car is warmed up. Especially if car is turned off after warm and started again. Noticeable at idle. Noticeable when applying load. When applying heavy load, the car will have a flashing check engine lights. Anywhere from 3-20 blinks. It will not always keep the light on afterward. Once the light is on steady, it stays until cleared. Again, intermittent problem steers me away from catalytic converter or bad valve or bad head.

Haven't done compression test because I don't feel a valve or head would be intermittent.

Seems like its happening when trying to go into closed loop?

I have also changed the ignitor as well now, to no avail.

Could it be a pcm? I'm so lost and have sunk Every penny into this. Help!!!!!!

The blinking light indicates the engine misfire is bad enough to risk damaging the converter from over heating.

Swap coils and determine if the code moves with the coil.

There is a service bulletin on these codes but may not apply.

https://www.carmd.com/Tsb/Download/26599/T-EG008-04

If really No 1 cylinder check fuel injector.

Are the spark plug wires installed correctly?

Read related topics on this subject below.

I have swapped everything, and it has New fuel injectors as well. I'll review the tsb you posted as well, thanks. The intermittent nature of it leads me to think electrical... can a cat issue be intermittent?

Check small wires to the coils.

How about engine coolant temp sensor?