Re: \'91 Samurai engine control problem
I would go through the EGR system and see that vacuum is correct at each component, and that the valve itself isn't sticking open. I would also check the MAP sensor to make sure it's putting out the right voltage. But unless you have a factory service manual, get prepared to be really, really confused. If you find the EGR valve sticking, try to clean it. A new one is very expensive and they are actually quite rugged and will take a lot of abuse. I have used carburetor cleaner a couple of times with good results. You can also dig a lot of carbon out of the passageways in the valve with a very small screwdriver or pick. If everything checks out, it could still be the ecm itself (ouch!).