I have had consistent maf sensor codes of both p0100 and p0101, along with misfire codes and occasional egr codes. I tried a new maf sensor, but instantly got the same p0100 code.Could this possibly be a bad ecm? Otherwise I still need to test the connector to see if that all checks out. Can someone explain how to test the connector, a pin out explanation etc?

Sorry, I forgot, it's a 1996 Subaru Legacy L wagon.

Did you replace the MAF with an OEM Subaru part or a cheap one from a parts house? More likely then not, it's a bad aftermarket MAF. the misfire codes can be related but the EGR code (probably a P0400) is not related.

Thanks for the response. Yes the maf was from O'Reilly's. They are so expensive though, do you think I could find a useable one from a junkyard as long as it was OEM? Also, has anyone out there even heard of a computer malfunction on one of these cars? Just curious because I once had one with my Olds Bravada. It had a tps code, turned out to be a bad ecm...

I'd probably try an oem junkyard one. ECU failures are exceedingly rare.

Yes, go to the junkyard!  I don't really think that a new maf  from O'Reilly would be bad, but you can't take a chance.  They don't fail that often so the junkyard is the best place to get a replacement and make sure it's OEM.   I've had to do it myself on a 90's car.  As DaveT said, don't fool with the ecu yet.

Thanks guys, I'll try that and see. I'm reasonably sure the EGR is a separate issue.It isn't moving like it should when I rev it up. I've seen some good YouTube videos on how to fix that. It's just strange that if unplug the MAF wiring connector and hold it close to the MAF, the engine dies and I start it up again it runs perfectly for a while!

they have "default" settings so you are not stranded by a sensor failure.  That may be coming into play.

Hey guys, I'm not sure if this forum has any rules about jump starting old threads (some forums have lots of silly rules) but I wanted to update this subject. I put working on this on the back burner for a few months, but recently I had some problems with my work truck that could not be fixed in a day, so I decided to take another look at my Sooby. I went to the junkyard found an OEM maf sensor. Slapped it in and presto! Car running strong again! Misfire codes eliminated by changing to a set of NGK plugs. Now I only have to check out the EGR. I just wanted to thank the forum and the guys who replied to my posts. I was skeptical about the aftermarket maf sensor's unsuitability, but you guys were right. Junkyard part that fixed my car for 22 dollars sure beat a $300 aftermarket part that didn't work. I hope anyone else with similar or different problems listen to their advice. They know what they are talking about, either through experience, sheer brilliance, or both!