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Discussion Starter · #22 ·
I want to thank everyone for their advice. Since my last post I replaced the PCV valve and cleaned and out baxk the OG MAF sensor. Noticed the idle in park is better but still have the hesitation when accelerating and the idling and hesitation it worse when I have the AC on. Plus now when downshifting it does it a little harder and the rpms are a lite off.

Next thought is the IAC and crankshaft position sensor. Any thoughts??
 

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I want to thank everyone for their advice. Since my last post I replaced the PCV valve and cleaned and out baxk the OG MAF sensor. Noticed the idle in park is better but still have the hesitation when accelerating and the idling and hesitation it worse when I have the AC on. Plus now when downshifting it does it a little harder and the rpms are a lite off.

Next thought is the IAC and crankshaft position sensor. Any thoughts??
To summarize, for everyone playing at home:

Hesitating on acceleration from a stop light
Idled ok for about 2 min then the RPM's started jumping then stalled
Ran the scan tool, came back with a MAF sensor code and a misfire code on all 6 cylinders.
Checked the vacuum hoses and all are good
Changed all 6 spark plugs, same issues
Van actually stalled on me a few times, once while idling and then twice at a stop light.
Changed the fuel pump today, same thing
Cleaned the throttle body with cleaner. Van began running higher RPM's
Pending code is P2196
And now, the original MAF is cleaned and reinstalled and you threw a new PCV on there

So, from the sound of it, all your codes are gone and idle issues are improved but you still have some hesitation on acceleration? Typically, hesitation on gear shifting and start-up are often an indicator that you need to do a drain and fill on the transmission fluid. If you had ongoing idle issues and you shift into gear at high RPM or have oscillating RPMs, it can strain your transmission internals and wear out your fluid faster. I'd pull the trans dipstick and check the color/condition of the fluid. It should be a bright red. If it's light pink or pinkish-brown, you should do a drain and fill and see how it performs. If it's fully brown or black, you should probably drop the pan, change the filter and may want to consider a flush.

While I was typing that, I saw you updated your post. The problem with firing the parts cannon is that now, you have introduced new parts, new problems, new symptoms, and uncertain diagnosis. For instance, if you replaced the plugs, but not the intake manifold gasket, you may have introduced a vacuum leak that you didn't have before. When you replaced the original MAF, it may have originally been a failed part which you replaced with a defective part and now you put the original, cleaned MAF back in and you have a marginally functional part (from cleaning).

In answer to your question for vacuum line routing, I recently posted pics of my '06 which should be the same as your '05. Where is this hose belongs to (comment #11). Hopefully, these help.

It may be that you still actually need a new (Denso) MAF or it may be that you need to disconnect the battery for a couple hours, reconnect, start the van and drive it through all its operating modes to rebuild the tuning maps. Whatever you do, from here on out, do NOT clear any more codes unless and until you conclusively diagnose and fix the actual problem. Even when you "think" you fixed the problem, you should still refrain from clearing the codes. If the problem is actually fixed, the codes will self-clear. If it's not, at some point, whoever looks at it will have information to work off of.
 

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Discussion Starter · #28 ·
Update:

After making sure the fuel pump was working, checking the pump relay and the EFI relay. Checking the fuel rails, fuel damper, changing all injectors. Checking both camshaft position sensors, all of which were good. The last thing I decided to check was the crankshaft position sensor, which was dead (ded dead). Planning on going to NAPA tomorrow to get a new one. Hopefully this has been the demon that has eluded me.
 

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Update:

After making sure the fuel pump was working, checking the pump relay and the EFI relay. Checking the fuel rails, fuel damper, changing all injectors. Checking both camshaft position sensors, all of which were good. The last thing I decided to check was the crankshaft position sensor, which was dead (ded dead). Planning on going to NAPA tomorrow to get a new one. Hopefully this has been the demon that has eluded me.
How did you determine this was bad? I would expect it would immediately throw a code if there was an issue with this sensor.

For the 2GR-FE engine (which you don’t have) this would have been a P0335 or P0339 code.
Toyota Sienna Service Manual: Crankshaft Position Sensor - Diagnostic trouble code chart - Sfi system - 2Gr-fe engine control system - Engine

And to be frank, I gotta echo what the other people are saying, which is slow down a minute. You are asking for advice, but seem to not be exploring the advice given and keep putting in part after part at this. This is not an economical nor time effective method of finding and fixing problems.
 

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Discussion Starter · #30 ·
The van is going to the shop to have them diagnose it. Van won't crank, no codes. At NAPA had them check the ohms in the crankshaft position sensor and it was good so, there's that. All the vacuum lines have been checked/replaced. I'll see what happens
 

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My 2005 Sienna had very similar symptoms as yours and I had just found the problem was with a cheap 3-month old MAF sensor. Last week the van stalled at a red light and it started hesitating on acceleration. My wife was lucky to be able to drive 40 miles home. Since then it always stalled on acceleration. I have tried to install 6 spark plug coils (plugs were only a few months old). After that the car would not start. Then I cleaned up the throttle body and still the same problem. I didn't think about the MAF sensor earlier because it was replaced 3 months ago due to an ignition issue on hot engine. Fortunately I still have the original MAF sensor. Today I put it on and the stalling and hesitating problems are gone. I already ordered a Denso one and will put it on tomorrow. The cheap $20 MAF sensor only lasted for 3 months. I saw your post a few days ago. Just registered this forum and wanted to suggest you to try an OEM MAF sensor.
 

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If you experience these symptoms and have no way to diagnose or resolve in the moment, disconnect the MAF then see if it runs better. There’ll probably be a a CEL but it might run well enough to get you home without stalling.

Sixto
‘04 LE FWD 200K miles
 

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Discussion Starter · #35 ·
I cleaned and replaced the MAF sensor with the Denso one to see if I noticed a difference, nothing. Unhooked it and it still won't start now. It wants to but just won't crank. Not sure what else to look at/check/change. If I can't figure it out today, it gets towed tomorrow to well respected shop. Talked with them the other day. Told then what I've done. They said to make a list, leave it in the van for them to narrow down. They seemed a little surprised it wasn't cranking after what's been done so far. Guess we'll see.
 

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Discussion Starter · #38 ·
*Update-issue found & resolved.

Turns out the clip holding the wiring for the crankshaft position sensor and oil pressure switch broke. That led to the wires resting against the belt and the belt cutting into the wires for the crankshaft position sensor. Mechanic said he's never seen this.

Put this one in your pocket for future reference.
 
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