I am having a big idle problem with the dreaded p1300-1305 random misfire codes.

I just cleaned out the EGR ports (which were completely clogged at 128k). But then I was doing further investigation into the EGR. Once all put back together, I unplugged the vacuum line plugged into the EGR and found it did not even have vacuum.

So if the EGR valve is not open during idle, when is is supposed to be open?

 

Its NOT open at idle for sure! It opens slightly when you accelerate. It fully opens under a load and when the ECU does the EGR moniter. There is a chance it could be stuck open at idle. Check the sensor input voltage at idle. If there is more than 1.25 volts, the EGR valve is slightly stuck open and should be replaced.

 

Yeah open EGR at idle would cause a problem.

It's mostly used at medium-low load steady state operation.