RatLabGuy

'89 Runner. Occasional random "stumbling" issues, will almost stall. jusy happens randomly for a few seconds, then goes back to normal.
doesn't seem to have the right response/power these days.

i pulled the engine code from the ECU. 31.

1 - what is the surefire way to clear the codes? I have tied both (a) disconnecting the battery, and waiting a while, and (b) pulling the 15A EFI fuse.
In both cases, as soon as I turn the key ON, it flashes 31 again.
So either...
- it's not really clearing, or
- it's something the ECU is picking up immediately

2 - I'm suspicious this is a vacuum related problem on the intake side. Is there a magic place to read the vacuum at idle? I have to really back the adjustment screw out to get it up to the 750rpm mark.

mudshuvelz

try spraying some brake cleaner or starter fluid around vaccum lines and intake gaskets with truck idling. Idle will increase if it sucks any in. as for the VAFM there are resistance specs that your can check on here somewhere. If you happen to find that it is bad I happen to have a known good one laying around here somewhere.