Hey all,
My CEL came on about 4 months ago and the California diagnostic code was 4, which is the air flow meter (sometimes called mass air meter, air flow sensor among others). My car has a flutter at idle and occasionaly has a surging idle (rpm from 600 to 10,000) but has otherwise been running well. I read quite a bit on this site about the issue and even got the local indies opinion. It seemed that most people were in agreement that the thing that goes bad on the meter was the potentiomer. Some were even replacing the pot before the CEL light came on in an effort to get rid of the flutter and surging. I gave it a while, but the surging seemed to be getting worse so. . .
I bought a potentiometer and decided to replace it today. It seemed like a simple enough procedure. I marked the position, took off the pot, replaced it with the new one and tested it with a multimeter. I moved the pot up and down until my reading with the DC voltmeter on pins #1 and #2 was between .65 and .75. It was swinging between those two readings and as it did so it surged. For those who have replaced it themselves, is it supposed to vary in the voltage or were you getting a solid number that wasn't really changing much? The surging and the flutter that I can feel at idle haven't changed. I reset the computer. We'll see whether the CEL comes back on.
So, all in all, kind of a disappointing day. I was hoping to take care of the CEL and get a silky smooth idle all in one shot. If the CEL comes back on, i'm not sure if I should then replace the Air Mass Meter in it's entirety or not. Is there anything else that can cause a #4 diagnostic code on a California car? Any thoughts, suggestions or criticisms would be appreciated.

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Eric Zacharias

'88 300 SEL
'64 Ford Falcon
'99 Infiniti QX4