sure, when unplugged the MAF , the PCM goes to limp home
and mimics the dead or missing MAF.
one reason, of many
is the AFR is lean, with maf present
then you remove MAF and the mimic goes horrid rich. (normal effect)
this huge rich hides the true cause of horrid lean.
see? 2 wrongs, make a right in this case.
its a 97, why are you scan too free.
connect it and see it fail. and why?
see all sensors. here. same engine, same all.
air leaks on this engine cause, lean.
a dirty mAF causes, lean. (clean it with carb spray 1foot away never close up)
clogged injectors cause, lean.
low fuel pressure causes lean.
if you put all the parts back and scan it
you'd see that.
you'd see the 0xysensor (Front) stuck lean B1S1. bank 1 sensor 1
try a new oxysensor front. first. so the scan tool can see true facts.
on a good engine, the 02 swings at idle
if that fails , i jump over that like at tick on a hound dog.
finding car parked and idling hot AFR issues, is easy with any scan too.
the EFI must be in closed loop at idle, hot, MUST.
does the maf read right at idle, ?
1.5-4.0 grams per second
or MAF output pin volts of. 1.7-2.0 volts
if the voltage is good ITS NOT THE MAF, its LEAN AFR.
AIR FUEL RATIO IS AFR. lean means FUEL STARVATION.
if you gun the throttle
the maf goes higher.
3v or 20grams/second.
here is me driving see MAF hit 55 grams/ a second.
Hills. do that.
the more HP the more Grams /per second, until max engine torque is hit. and RPM max HP.
here is live data plot of a 96 MAF
the blue line is THROTTLE ANGLE> im driving aggressive as heck.
if the maf tests good, its not the MAF>
its easy to test.