Toyota Sienna Forum - siennachat.com banner
1 - 20 of 38 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter · #1 ·
I have a 2005 Sienna XLE Limited that recently started hesitating on acceleration from a stop light, then a slow turn. The following morning it started fine, 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.

I replaced the MAF, no fix. 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. At this point I'm just not sure what else it could be. I thought the fuel pressure switch but not sure.

Anyone have any ideas????
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #3 ·
My first thought is if you replaced the MAF with a non-Toyota brand you may not have fixed the problem. Also, your air filter isn't 10 years old or anything, is it? :)
No, air filter is not 10 years old lol. Had it changed with the oil. I checked that as well to make sure, normal light dirt.

I cleared the codes after the MAF was replaced. I'm waiting for the CPU to cycle and see if it throws anything back.
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #4 ·
No, air filter is not 10 years old lol. Had it changed with the oil. I checked that as well to make sure, normal light dirt.

I cleared the codes after the MAF was replaced. I'm waiting for the CPU to cycle and see if it throws anything back.
I did not replace the MAF with a Denso one. Those aren't cheap, is there a way to know of that's the problem before buying it?
 

·
Registered
Joined
·
51 Posts
I did not replace the MAF with a Denso one. Those aren't cheap, is there a way to know of that's the problem before buying it?
Sadly no, but the MAF is one of those things that the computer is very picky about.
Also (unrelated) try to keep your replies in one post instead of double posting. The alert that a reply was posted only includes the first reply so no one will know you posted the second one until they visit the forum - and if they can't help with the first, they won't know they can help with the second because they won't revisit the forum.

It's weird, I know. It's just how forum software works.
 

·
Registered
Joined
·
1,165 Posts
I did not replace the MAF with a Denso one. Those aren't cheap, is there a way to know of that's the problem before buying it?
If you still have the original MAF, clean it with MAF cleaner and reinstall it. Live data is the way to go. It could be leaning out or flooding out. Without live data, there's no way to tell. Only a way to guess. That said, my guess is that you might have bad O2 sensors. When the car first starts, it ignores the O2 sensors. After a couple minutes, it switches to use the data from them, which could explain the problems. My next guess would be a vacuum leak in a plastic housing. When ice cold, the leak is closed. When it warms up a bit and the plastic expands, it opens up the leak. The live-data scanners can be bought for as little as $15 for a Chinese-made Bluetooth reader and a $5 Torque Pro app purchase. They can't do everything, but they work fairly well.

As @Roader alluded to, you should replace the manifold and throttle body gaskets and clean the throttle body when doing the plugs. If you don't replace the gaskets, you can create a vacuum leak as you torque an already flattened gasket to specified torque settings.

Now, for the harsh news... You're talking about the expensive price of a Denso MAF ($75), but you seem to be firing the parts cannon right and left. You "saved" $30-40, but spent $$$$ on spark plugs, an off-brand MAF and a fuel pump plus all the labor. You would probably have saved a lot more if you properly diagnosed (or paid someone to properly diagnose) the van FIRST.
 

·
Registered
Joined
·
51 Posts
You would probably have saved a lot more if you properly diagnosed (or paid someone to properly diagnose) the van FIRST.
This is probably true. With computerized vehicles it's often better to just drop it off with a mechanic for an hour, go have a hamburger, and get a targeted Christmas list of things that need replacing. In your case, I'd still try the name brand MAF. If that doesn't work I'd let a mech put it on a computer and diagnose for $100. Sometimes you can find a coupon for a free diagnosis online with your dealer too.
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #10 ·
Fortunately I did the fuel pump and plugs myself so saved a ton on labor. I talked to a couple mechanics that have retired that I know and got their opinion originally. It came down to MAF, vacuum hoses or fuel pump to them. All of which have been changed ot checked.

I was going to put in the shop to see of they could figure it out. Coming here was a last ditch effort to see what the group had to say. I was going to clean the throttle body today to see if I notice a difference. I've driven the van 3 times since clearing the codes and still nothing (about 40miles). Not sure if the PCV valve or the fuel pressure switch would be a problem with these symptoms or not?
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #11 ·
Update
Cleaned the throttle body with cleaner. Van began running higher RPM's(1000 with AC compressor on, slightly higher with it not). Down shifting became harder than usual. Because I cleaned the throttle body, I has to detach the MAF so it triggered the check engine light.

Got back home and hooked up the scan tool. Stored codes are P0102 and P0113. I'm assuming because I had the van on with the MAF disconnected.

Pending code is P2196 O2 Sesnor Signal Biased/Stuck Rich Bank 1 Sensor 1. Thoughts on relation to what I've been experiencing
 

·
Registered
Joined
·
1,165 Posts
If you cleaned the TB by spraying cleaner into it (as opposed to spraying cleaner on a rag and wiping it) and then disconnected the MAF, I'm not sure there's any value to any codes that popped up. That said, I still would spray the original MAF down with MAF cleaner, let it air dry and then reinstall it. At this point, if you're going to have someone look at this, they're going to have to double check all the work you did PLUS investigate the original issue.

Is your scan tool just a code reader or can you pull up fuel trims, O2 voltages, etc?
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #14 ·
My reader does have live data and freeze frame on it. I'll run the live data and see what it says. I guess I'll reinstall the OG MAF after a cleaning and see what it says.

Thanks for all the good advice.
 

·
Registered
Old Sienna
Joined
·
657 Posts
Had a Nissan minivan with a weird problem. Idled fine but under acceleration would die, then accelerate, then die.... It was like riding a bucking bronco. The 3" plastic tube between the air cleaner and manifold had a crack in it. Under acceleration the engine would rock backwards and open the crack. Dying would rock the engine forwards and close the crack. etc. Fixed it with a can :)
 

·
Registered
Joined
·
3 Posts
If you still have the original MAF, clean it with MAF cleaner and reinstall it. Live data is the way to go. It could be leaning out or flooding out. Without live data, there's no way to tell. Only a way to guess. That said, my guess is that you might have bad O2 sensors. When the car first starts, it ignores the O2 sensors. After a couple minutes, it switches to use the data from them, which could explain the problems. My next guess would be a vacuum leak in a plastic housing. When ice cold, the leak is closed. When it warms up a bit and the plastic expands, it opens up the leak. The live-data scanners can be bought for as little as $15 for a Chinese-made Bluetooth reader and a $5 Torque Pro app purchase. They can't do everything, but they work fairly well.

As @Roader alluded to, you should replace the manifold and throttle body gaskets and clean the throttle body when doing the plugs. If you don't replace the gaskets, you can create a vacuum leak as you torque an already flattened gasket to specified torque settings.

Now, for the harsh news... You're talking about the expensive price of a Denso MAF ($75), but you seem to be firing the parts cannon right and left. You "saved" $30-40, but spent $$$$ on spark plugs, an off-brand MAF and a fuel pump plus all the labor. You would probably have saved a lot more if you properly diagnosed (or paid someone to properly diagnose) the van FIRST.
True, IF. He many of us (notice everyone’s holding their hand up) have had a dealer ‘diagnosis & fix’ then say, ‘Whoops, that didn’t work, it’s this OTHER thing-a-majiggy,’ and we need to replace it.
 

·
Registered
Joined
·
1 Posts
I have a 2005 Sienna XLE Limited that recently started hesitating on acceleration from a stop light, then a slow turn. The following morning it started fine, 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.

I replaced the MAF, no fix. 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. At this point I'm just not sure what else it could be. I thought the fuel pressure switch but not sure.

Anyone have any ideas????
Those old Siennas had a problem with unbalanced tires causing drivability problems. I found out that having unbalanced tires cause a vibration that affected the computer in some way to cause stalling and shutting down the engine. The unbalance problem was minor but on drives of 600 miles or so the engine would shut down and I needed to clear the codes to get moving again. I went through the diagnosis procedures you are going through but only getting rid of the vibration fixed my problem. Check into this aspect of drivability.
 

·
Registered
Joined
·
13 Posts
I have a 2005 Sienna XLE Limited that recently started hesitating on acceleration from a stop light, then a slow turn. The following morning it started fine, 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.

I replaced the MAF, no fix. 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. At this point I'm just not sure what else it could be. I thought the fuel pressure switch but not sure.

Anyone have any ideas????
I'd check the coil packs.
 

·
Registered
Joined
·
53 Posts
Had a Nissan minivan with a weird problem. Idled fine but under acceleration would die, then accelerate, then die.... It was like riding a bucking bronco. The 3" plastic tube between the air cleaner and manifold had a crack in it. Under acceleration the engine would rock backwards and open the crack. Dying would rock the engine forwards and close the crack. etc. Fixed it with a can :)
Had a similar issue with an 86 Toyota Van. Was going to mention that. Check for cracks and leaks. Get a propane canister torch and turn the gas on but don’t light it. Poke that around the air intake ducts vacuum hoses and throttle body. If there is a crack the gas will get ingested and increase the idle speed. Some sprays will work too like carb cleaner but not so safe for some plastics.

RPM fluctuations sounds like an intake leak.
 

·
Registered
Joined
·
13 Posts
Worked on a Toyota echo years ago that would idle perfectly but stall instantly when you stepped on the gas. Removed the maf with a couple Phillip's screws, sprayed it with carb cleaner (sorry, didn't have maf spray) and reinstalled it, problem fixed. I was amazed; all took about 10 minutes.
 
1 - 20 of 38 Posts
Top