I picked up a used AFM for my 22RE today at the boneyard. I removed the old and intalled the new, started it up and it could barely maintain idle. It also stumbled throughout the RPM range.

Put the old one back on and it ran much smoother again.

My question is: Would swapping the AFM impact other calibration - i.e., throttle setting or timing? Or should it be straight plug and play and do I likely have a bad unit?

My old AFM was functioning fairly well, but I was having some intermittent idle stumbling. My main driver for replacing it was that a mechanic I had previously gone to drilled out the plug on the adjustment screw on the AFM and had played with the factory calibration. I now have no idea what its set to and thought a relplacement would help bring that back in check.

I wonder since my original AFM had been tampered with if the timing and idle setting I had now need to be reset to the new AFM or do I just have a bad one?

 

You can try pulling efi fuse or battery cable to reset ecm, but it sounds like a bad meter.

 

I agree; sounds like a bad VAFM.

 

Are the part numbers the same? There are multiple versions. Some look the same and some don't. Some mount the same and some don't. Some that are different can still be swapped and some can't.

 

Yes. Part #s are the same. I checked that before I bought it.