Yet another TPS/APPS/Throttle Body WTF???!!! Thread... (1 Viewer)

[Voypescado]

Ok...So first off let me extend a big thanks to this forum for providing me with an INSANE wealth of info on trying to diagnose this one but alas, my hours of endless Mud reading have left me with a few lingering questions.

Consequently, I've got to request some additional advice from the resident experts before proceeding.
Brief overview of symptoms:
2005 Lx470 220,000 on the clock
Intermittent stalling/ throttle input failure at both low and high speed only occurring in below freezing temps
Hard start/ brief turn-over followed by stall in below freezing temps
Christmas Tree dash (CEL, VSC, Blah Blah)
Previous scans turned up MAF codes but repeated cleanings and replacement OEM MAF have little long-term affect. (Haven't ruled out a wiring issue)
Both upstream A/F sensors replaced last year with Denso units

She nearly left me and the fam stranded on Christmas Eve so I've decided it's time to throw some money at this thing. Also...we're down to one vehicle after some DA ran a stop sign last week and totaled our fully built 3rd Gen Runner (Literally the best vehicle I've ever owned, no offense to the Hundo Mafia). Fingers crossed that insurance pays out anything close to the actual value of that 'ol girl!

Anyway, after diggin' into this topic, I think I've actually decided that I'd rather just pony up the money and swap out the whole throttle body/throttle body assembly in hopes of tackling as many variables as possible in one go.

Here's what I'm looking at:

2002-2005 Toyota Throttle Body 22030-50170 | Camelback Toyota Parts

2002-2005 Toyota part # 22030-50170 - Throttle Body

parts.camelbacktoyota.com

I plan on putting in a call to these guys on Monday as they've always been super great to work with in the past but I guess my questions are as follows:
1.) Does this part/ part number include the TB/TB Motor and TPS? (Price seems lower than what I've seen referenced elsewhere.)
2.) In the 2005, am I correct in assuming that the APPS is located at the pedal and should I turn my attention to this guy as a possible culprit?
3.) Should I just order a new TPS, Clean the mess out of the existing TB and call it a day?
4.) Should I be giving more credence to that original scan that pointed a finger at the MAF?

Any input is hugely appreciated and Merry Christmas guys!

 

[Eicca]

I recall another guy with similar symptoms who eventually tracked it to a loose pin at the ECU.

I also had a Lexus with a 1UZ that had some MAF issues that were actually a bad plug. I soldered in a new pigtail and it was totally fine after that.

 

[Fsikalasinh]

Have you checked for vacuum leaks by chance? I had similar symptoms when changing the starter and took bad advice on reusing the intake manifold gaskets. It would have the symptoms above and codes.. finally sprayed some cleaner around the manifolds and it revved it.

Bought new gaskets, retorqued and all was well after.

 

[87warrior]

The first thing I would do is check realtime OBD data and watch it closely whenever your issue starts. I'd start by watching the MAF, intake temp, coolant temp, throttle position, vacuum and fuel trims to see if anything obvious is out of whack. I certainly wouldn't throw parts at the vehicle hoping it might fix a problem without doing an investigation.

I recall another guy with similar symptoms who eventually tracked it to a loose pin at the ECU.

I also had a Lexus with a 1UZ that had some MAF issues that were actually a bad plug. I soldered in a new pigtail and it was totally fine after that.

Hey, that was me. What a wild ride diagnosing that was. My symptoms were almost identical to @Voypescado except I never had a CEL.

Low RPM surging and stalling

I just returned from a drive across Kansas and experienced an extreme surging RPM during the last 1/2 of the drive. Traveling with a 2,500# trailer in 95°F temperature. Started the trip with gas from a station I always get fuel from. Hit the road at 65mph. Cruiser was running good, with...

forum.ih8mud.com

 

[Voypescado]

Thanks for the replies thus far guys.

I also came across the loose ECU pin post and definitely haven't ruled that out.
And the vacuum leak suggestion is a possibility but the fact that this issue only occurs in below freezing temps and the truck behaves perfectly all summer long has me leaning hard towards faulty electronics/ sensors or sticking/lagging mechanical components.

We're done making the holiday rounds so I'm going to dig into her tomorrow to do some further diagnosing. First on the agenda is actually getting eyes on this trucks throttle body to verify what exactly I'm working with here. Based on some additional research I'm pretty sure my 2005 LX is entirely drive-by-wire and may not even have the TPS that I've seen mentioned elsewhere as a possible point of failure in earlier 100's with a hybrid TB assembly.

As for the scans, my bluetooth OBD set-up is still plugged into my 4Runner which is currently still sitting in the impound lot. I'm planning on swinging by tomorrow to grab it along with a few other things.
I was actually looking into ordering a cable and downloading Techstream specifically for use with this truck but the sketchiness of bootlegged Chinese software downloads and potential 3rd party access to a tablet I use for my business has me second guessing that one.

I will definitely keep everyone posted and thoroughly document my efforts with this one as it seems like this breed of gremlin is something not entirely uncommon to the 100 series' and any potential solutions could be of benefit to anyone trying to diagnose similar issues.

 

[AlpineAccess]

Thanks for the replies thus far guys.

I also came across the loose ECU pin post and definitely haven't ruled that out.
And the vacuum leak suggestion is a possibility but the fact that this issue only occurs in below freezing temps and the truck behaves perfectly all summer long has me leaning hard towards faulty electronics/ sensors or sticking/lagging mechanical components.

We're done making the holiday rounds so I'm going to dig into her tomorrow to do some further diagnosing. First on the agenda is actually getting eyes on this trucks throttle body to verify what exactly I'm working with here. Based on some additional research I'm pretty sure my 2005 LX is entirely drive-by-wire and may not even have the TPS that I've seen mentioned elsewhere as a possible point of failure in earlier 100's with a hybrid TB assembly.

As for the scans, my bluetooth OBD set-up is still plugged into my 4Runner which is currently still sitting in the impound lot. I'm planning on swinging by tomorrow to grab it along with a few other things.
I was actually looking into ordering a cable and downloading Techstream specifically for use with this truck but the sketchiness of bootlegged Chinese software downloads and potential 3rd party access to a tablet I use for my business has me second guessing that one.

I will definitely keep everyone posted and thoroughly document my efforts with this one as it seems like this breed of gremlin is something not entirely uncommon to the 100 series' and any potential solutions could be of benefit to anyone trying to diagnose similar issues.

Any update?

 

[Voypescado]

Couple of updates on the LX post tear-down and what not.

First off let me start with a PSA:
These trucks are great, I mean really freakin' great. But most of our 100 series our bumping 20+ years and with that, legendary reliability aside, comes some requisite upkeep.
My rule of thumb on used vehicles holds as true for this 'ol girl as it has for every other 150,000+ mile 4x4 I've ever purchased:
*Buy the newest, cleanest, most rust free and well-maintained truck you can afford...and then plan on spending at least double what you paid for it building the sob into a rig you can confidently take cross-country and back.

Unfortunately, after 3+ years of turbulent courtship, I'm just now getting intimate with this 'ol girl . (still talking about the LX here).

Here's where we stand on the aforementioned symptom diagnosis:
Tear-Down produced a NUMBER of findings that could have been contributing to the issues described in my original post.
1.) Upon removal of air box/intake hose/air cleaner assembly etc. I noticed that every hose clamp/spring clamp on every vacuum line, as well as the large clamp on the main air intake hose @ the manifold were so loose you could spin them by hand. (props to Fsik on the possible vacuum leak tip)
2.) Throttle body was filthy. Like probably hadn't been cleaned in 230,000 miles filthy.
3.) PCV hose was cracked at the valve cover and TB and spewing oil crud all over the place.

As usual, my solution to the problem (in the absence of any actual, technical, knowhow) was just to throw some parts at it.
Here's what I came up with for round 1:

OEM Throttle Body: Toyota (22030-50170)

2002-2005 Toyota Throttle Body 22030-50170 | Camelback Toyota Parts

OEM Throttle Body Gasket: Toyota (22271-50042)

1998-2005 Toyota Fuel Injection Throttle Body Mounting Gasket 22271-50042 | Camelback Toyota Parts

OEM Plugs (Iridium): Toyota (90080-91180)

1992-2012 Toyota Spark Plug 90080-91180 | Camelback Toyota Parts

Valve Cover Gasket: Toyota (11213-50031)

1998-2009 Toyota Engine Valve Cover Gasket 11213-50031 | Camelback Toyota Parts

Spark Plug Tube Seal: Toyota (11193-50010)

2001-2009 Toyota Spark Plug Tube Seal 11193-50010 | Camelback Toyota Parts

PCV Valve
Toyota (12204-50030)

While I'm aware that a good portion of this crap has nothing to do with the original issues I outlined, I must confess that I suffer from a debilitating illness known as "WhileImInThereItus". In layman's terms, I figured since I was way past due on some top-end pm. why not do valve cover gaskets, PCV etc. in addition to the TB assembly and vacuum hoses which I suspect may be more pertinent to the problem.

Anyway, as I feared, this posts utility has been far exceeded by its word count so I'll shut up now and get back with ya'll after I've got everything put back together and had a chance to put some miles on her with the new TB and remedied vacuum leaks.

Also planning on investing in a decent scanner/Techstream set-up between now and then to ensure that when this issue arises in the future (as I suspect it will) I can get some decent real-time diagnostics on this thing and take a more targeted approach.

 

[Voypescado]

And just for entertainment value, while the LX is tore apart and I wage war with insurance companies on recouping the value of my totaled 3rd gen Runner...I managed to snag this gem to get me from A-B (albeit very slowly) in the interim:
1 Owner, 1994 Reg. Cab Pickup 22RE 5spd 4x4 (Still had a folder full of dealer maintenance records and the window sticker!)
98,000 on the clock and rust free!
Affectionately dubbed "Little Blue" by the Girls.
Stay tuned for a full build on this one (posted in the appropriate sub forum of course)