1999 4runner hesitation

He said there could be a problem with the MAF but he didn't do anything to
it. I took it out the next day and cleaned it, but did not do any
diagnostics with it (I don't have a book explaining what to check for). I
also bought a Bank 1 Sensor 1 oxygen senson, but the toyota technician told
me that I do not actually have an oxygen sensor, but instead I have an
Air/Fuel ratio sensor (California emissions system). I have searched the
web and have not found anything that distinguishes between an oxygen sensor
and an A/F sensor for this model year.


"DJ Ducky" <am.DeleteThis@apl.washington.edu> wrote in message
news:c49d0g$ccs$1@nntp1.u.washington.edu...
 > P1133 HO2S Insufficient Switching Sensor 1
 > P0172 System too Rich (Bank 1)
 >
 > Did they check your O2 Sensor? or maybe or MAF sensor?
 >
 >
 >
 >
 > "tjh" <tedhiggins.DeleteThis@charter.net> wrote in message
 > news:106f9h3a1ir356c@corp.supernews.com...
  > > I have had a problem with hesistation when the accelerator is first
  > > depressed, in my 4 runner for several weeks. While trying to diagnose
the
  > > problem, I would open the throttle body by hand in the engine
compartment.
  > > It takes about a second after turning the throttle body for the engine
to
  > > rev. At the same time I can hear a low whistle or 'cshhhh' coming from
 > the
  > > back of the engine near the firewall. I thought it might be a vacuum
 > leak,
  > > but I couldn't find one. After a couple of weeks of this my 'check
 > engine'
  > > light came on and I am getting codes P0172 and P1133. Can anyone
suggest
 > a
  > > good site to go to for some troubleshooting advice or info? Or, does
 > anyone
  > > know what this problem is? I took it to the dealer. Their master
  > > technician spent an hour with it and just scratched his head (they
didn't
  > > even charge me because he had no idea what the problem is). Any help or
  > > advice is appreciated.
  > >
  > >
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: 1999 4runner hesitation 

I have a 98 4runner limited and I am having the exact same hesitation
you are talking about. I can rev the engine from the engine compartment
and there is almost a sec delay before the engine revs. Also there are
times during acceleration the engine runs smooth and then sometimes it
sputters. I am receiving trouble codes P-100(MAF sensor error circuit)
P-110(IAT sensor circuit) and some random cylinder misfire codes. The
cylinder misfire codes are most likely to be caused by the MAF or IAT
malfunctioning. I have changed and checked all wires and sparkplugs.
Since the error codes say sensor circuit there is most likely just a
bad wire somewhere. I bought a MAF from a salvage yard(pick a part) and
that did not solve the problem. Those bastards are expensive. Any
Advice????



P.S. The trouble codes you listed, TJH, are; P-0172- System Adaptive
fuel too rich, & P-133 (I assume you typed one to many ones, since
there is not a code 1133)- Upstream heated O2 sensor circuit low
voltage (Bank 1, Sensor 1)
 >> Stay informed about: 1999 4runner hesitation 

I too have this low rpm hesitation problem. I also have a tapping noise
when accelerating between stop and 40mph. In 2 years, I've replaced a
starter and dealt with a "Bank Lo Lean" check engine code (that suddenly
stopped) and now the hesitation at low speeds and the "tapping" noise.
The tapping source sounds like passenger side, low on the engine. I've
had great luck w/ Toyotas, but my patience is wearing thin with this
thing. I've heard suggestions to:
1. change fuel filter
2. Add Chevron Techron FI cleaner
3. Clean MAS sensor

Any ideas on what I should try (above or others)?
 >> Stay informed about: 1999 4runner hesitation 

I am having the same problem. Are you having any Luck ?
 >> Stay informed about: 1999 4runner hesitation 

I am having the same problem. Are you having any Luck ?
 >> Stay informed about: 1999 4runner hesitation 

I am having the same problem. Are you having any Luck ?
 >> Stay informed about: 1999 4runner hesitation 

I am having the same problem. Are you having any Luck ?
 >> Stay informed about: 1999 4runner hesitation 

I am having the same problem. Are you having any Luck ?
 >> Stay informed about: 1999 4runner hesitation