I've located the ECU and it is blinking 12 times, then stopping, then
blinking 12 times, stopping again, etc.
If I am correct, twelve blinks pertains to a problem with the EGR.
What usually goes wrong with the EGR, how much does it cost to fix and
is it servicable by a backyard mechanic?
The symptoms suddenly started a few weeks ago; rough idle and running,
gas mileage under 15 MPG and a longer than usual time to warm-up.
Thanks again in advance,