Originally Posted by dsandmire
I have an occasional "34--MAS" even after the new MAS but it is not concurrent with the missing/shake. Most recently, I was getting a periodic 13 so replaced o2 sensor.
I've read in the forum that replacement parts could also be a problem--in this regard, I guess both the rebuilt MAS and the ECM could be suspects.
Yes, there have been posts about suspect replacement parts. Bosch O2 sensors and the level of accuracy of MAF replacements. Had to diagnose those unless you have more than one part...causing different results.
With your code 34, I have to wonder if you've looked at the MAF plug? Maybe you're getting an "iffy" connection there? MAM makes a tester for this specific plug.
There's also nothing wrong with taking it in for a formal diagnosis. Electrical can be VERY tricky though. I remember one guy going nuts until he rewired the circuits ALL the way from his ECM to his MAF. But, I don't think you need to do that.
When you get normal operation at higher rpms (higher voltage), I have to wonder if you're getting some drop-out on the feed wire in the MAF plug. Clean the contacts as well as you can. Plug/unplug a few times. Then re-try.
I was having an intermittent issue with idle...then did the same. I even used dialectic grease (but was told it was an insulator...not conductor. LOL Still...somehow...the problem went away by focusing on cleaning those MAF plug contacts. And, it's been gone for 2yrs.
Also was getting code 34 at the time. I'm still running my original MAF.