[Shotimes] OT: '93 Ford Ranger Error Codes

[Josh Salaets]

I am hoping you guys can help me diagnose a problem with my grandparents' '93
Ranger 3.0 AT with 73K miles on the clock. For quite a few years, the truck
has often started bucking (surging) after being driven for a long time (100+
miles). During this time, the "Check Engine" light turns on. It is difficult
to even keep it at 55 mph, and it often downshifts to stay there - it's as if
I'm climbing a steep hill, yet I'm on level ground. If I get on it real hard,
it'll clear up and accelerate fine, but as soon as I start cruising, it comes
back. This problem comes and goes at random - sometimes it will go away if the
truck is turned off and back on, while other times it takes a full night of
cooling off for it to go away. I have ran the codes before, and it showed the
left bank was running lean.

This really wasn't a problem until I took the truck to Idaho this last week -
it acted up REAL bad once on the way there, and on the way home, I had to
fight it ALL the way back - 430 miles!

I ran the codes when I got home. There were no KOEO or KOER codes, but I came
up with a TON of Continuous codes:

  a.. 171 - No HEGO switching detected/adaptive fuel at limit (RH)
  b.. 172 - HEGO snesor indicates system lean (RH)
  c.. 173 - HEGO sensor indicates system rich (RH)
  d.. 175 - No HEGO switching detected/adaptive fuel at limit (LH)
  e.. 176 - HEGO sensor indicates system lean (LH)
  f.. 177 - HEGO sensor indicates system rich (LH)
  g.. 188 - Adaptive fuel lean limit is reached (LH)

It would seem both 02 sensors have bit the dust, but it seems odd both of them
have died. What do you guys think? Would faulty O2 sensors create this bad of
driveability issue, or is there something else I should be looking for?

I was thinking it could be clogged cat(s), but this would likely be a constant
problem instead of intermittent. I was also wondering if a bad MAF or TPS
could cause this, even if they aren't showing up as being bad during the test.
Is there another sensor that could cause this?

Any help would be GREATLY appreciated, as I would like to get this problem
fixed by tomorrow, since the truck is going to Colorado Tuesday.

If I do need new O2 sensors, anyone have recommendations on what brand I
should buy or where I should go (we have Autozone, Napa, Schucks, and a few
other local parts stores)?

Thanks A LOT, and sorry for such a long OT post!!!

Josh Salaets
95 SHO MTX (See it at: www.cardomain.com/id/sh0gun)
85 Omni GLH-T (Yeah, it's fast)
NWSHOC Member
Eugene, OR