[4Runner93]

Hey guys, so went to look at a 99 today and mr an my dad test drove it. When checking the outside for cosmetic stuff, the engine would idle at ~800-900 but would surge and sound like it was almost going to die. When I watched it, it would bottom at 500 before recovering to 900. Any idea of what it could be? The seller said it could either be the throttle body needs cleaning or an air idle sensor...anything else it could be?

[animal]

MAF might be dirty as well.

[Headly]

where is the air idle sensor?

[Jordan Petry]

Could also be your Idle Control Valve. The valve you are referring to is the EACV, electronic air control valve. That could be bad. I would also load test the alternator. It could be revving up to try and get more power to run the car, and then idling down because of lack of power.

[bak3rme]

been having this problem for a while. i wish i could fix it!
i've cleaned the IAC valve
cleaned TB plenty of times
cleaned MAF
replaced sparkplugs/ wire set
replaced fuel filter
been running injection cleaner from cheveron every 5 fillups or so
been filling up with only chevron and shell gasoline

still i get these surges when at idle...and it still shuts off every now and then...

what else to do???

[brian2sun]

Surging is usually associated with a bad TPS (throttle position sensor). Dirty IAC is usually stumbly and rough idle and dirty MAF usually causes hesitiations as well as bad idle. The TPS can be tested for resistance, but they aren't too expensive to replace.

[bak3rme]

Originally Posted by brian2sun

Surging is usually associated with a bad TPS (throttle position sensor). Dirty IAC is usually stumbly and rough idle and dirty MAF usually causes hesitiations as well as bad idle. The TPS can be tested for resistance, but they aren't too expensive to replace.

TPS replacement. talk more plz!
edit* not that i want to go replacing stuff..but just some more info i can store

[brian2sun]

I was getting surging and after research and cleaning everthing else I could, I tried out an Autozone TPS for ~$15 IIRC. I didn't plan on actually using their crap parts, but I figured for $15 it was worth that to see if it made a difference. It did so I took it off, cleaned it up, brought it back, got my $$ back and bought an OEM one off ebay for ~$60. Problem solved and it's been about a year since.

[xcmountain80]

Pricing a TPS

[4R99JB]

Originally Posted by brian2sun

I was getting surging and after research and cleaning everthing else I could, I tried out an Autozone TPS for ~$15 IIRC. I didn't plan on actually using their crap parts, but I figured for $15 it was worth that to see if it made a difference. It did so I took it off, cleaned it up, brought it back, got my $$ back and bought an OEM one off ebay for ~$60. Problem solved and it's been about a year since.

Thanks for sharing your experience. It's posts like these that make this a great forum for sharing AND learning.

[xcmountain80]

Still pricing

[xcmountain80]

Anyone have a part number, Toyota is telling me this is a complete kit and come with the throttle body..... (sensor not sold separately).

A

[thebrandon]

Everyone beat me to it. I was going to suggest the TPS as well.

Check rock auto. They have them for my 2000 3.4L from $30-46. However it is not an OEM one I think.

[xcmountain80]

I replaced the alternator and can watch the amperage it is producing and that’s not the culprit. I have a 2002 4RUnner and the TPS is not sold separately, whole throttle body only.

Helpful to fully understand what is happening
http://www.ttora.com/forum/showthread.php?t=13283

Thread I started trying to address the TPS specifically and gather more data
Throttle Position Sensor.....?

Aaron

[xcmountain80]

I'm wondering if this may be indicative of a failing battery? I'll stop by autozone and have them give it a look.