2006 Sequoia misfire?

Running sluggish/jerking at start up putting it in gear.These are the codes its showing. Not sure what it means

 

Has oil in the sparkplug tubes and on the coil after replacing the valve cover gaskets

 

Left out some small details there bro: What all work has been done to the truck in the last 6 months or 10k miles?

The codes in the 1st pic immediately had me thinking "oh snap, the ECU can't figure out the right air/fuel ratio on both banks! Something is wrong with the MAF or timing!

Then I saw the 2nd pic, and that's like a shitload of electrical haywireness, which tells me you probably have an issue with grounding somewhere, or your ECU went completely nutso. I'd verify your grounds.

When you did the valve cover gaskets, did you also do the spark plug tube seals like you're supposed to?

 

I'm still trying to decipher this paper but it doesn't look like all these codes are actually present it looks more like a general code set that may be related to the code in the top left of the first page P0174. Just guessing here. Paperwork is a little confusing.

 

Ah, I missed that. In that case ...

The fact it's an air/fuel ratio problem across both banks is suggestive of it being one of two issues:

• Inconsistent air flow OR air flow sensing issue between the throttle body and air filter - i.e. MAF is bad or needs to be clean, it's not giving consistent airflow data to the ECU, so the ECU can't mix air/fuel properly, or a throttle position sensor isn't properly sensing how open the butterfly is, for example.
• Inconsistent fuel delivery - i.e. the fuel pressure regulator could be bad, fuel pump is in process of failing and not pumping adequate fuel to the rail.

EDIT: OK wait, I misread the sheet again, it's only one code and impacting bank 2. Probably KNABORES is correct below. Upstream O2 sensor is toast, and ECU can't get a good read on the combustion mixture, so it's not sure where/how to manage fuel delivery.

Ignore all this crap I typed before, the following is what I'd do if this was actually an a/f problem across two banks.

Without knowing how many miles are on the truck/SUV, I'd lean towards the MAF before I'd suspect the fuel pump. If the fuel pump has ever been replaced, I'd want to know if the replacement was Denso/OEM or not.

First step I would take is to pull the negative battery cable while you clean the MAF with CRC MAF cleaner, which you can buy in a spraycan at the LAPS. If you need help on cleaning MAF, LMK, I can get you a video off YouTube form the Toyota Maintenance Channel. You probably need to clean it anyway. If you are over 200k miles and still on the original, I'd consider just replacing it. Buy Hitachi brand, it's what Toyota used for OEM. DO NOT buy it on scAmazon or fleaBay.

Diagnosing the fuel pump won't be so easy. Easiest way is to measure the fuel pressure. This is discussed in the field service manual.

 

I had a shop replace the gaskets. I dont know if they replaced the seals or not. Oil in the spark plug tubes is an indication that they didnt replace them, but i'm not sure

 

I cleaned the MASS and replaced the plugs, but it didnt help.

 

273k miles on it

 

Got a junkyard nearby you can yoink the MAF off of another 2UZ-FE truck?

Do you have any way to confirm fuel pressure?

EDIT: Nevermind, I misread the damn sheet again. I thought it was throwing four codes. I don't like the way this stuff was printed out, it's confusing as shit.

 

I'll call the junkyard to see if they do. I havent checked the fuel pressure. I just know that oil is getting in some of the sparkplug tubes, maybe they didnt replace the seals while replacing the valve cover gaskets. Its been a couple months since the shop replaced them. They might try to charge me again since its been that long ago.

 

I mean, it’s take a couple of months to find something like that.

Meanwhile, that oil in the spark plug tubes is not good, but also not what’s causing your fuel delivery or air/fuel mixture problems (hence codes). But if they were inside your valve covers, fuel lines *are* in the way of removing the drivers side valve cover, and we just had a guy on here just yesterday who broke one of his fuel lines pulling his valve covers by nudging or tapping it… so so if that was just 6-8 weeks ago they did that work, you may’ve found your other problem.

 

If it’s just code P0174, fuel trim lean bank 2 (passenger side), then it could be as simple as an O2 sensor. Could be a vacuum leak. Could be the MAF, but unlikely with only one bank affected. Recent work has me thinking the mechanic left more than the spark plug tube seals off.

 

Reading this, I just realized I misread the report again. It's only one code. So one bank. Shit, I'm just gonna hafta keep editing/deleting what I'm writing here.

I concur, the upstream O2 sensor on the passenger side is probably the culprit. ECU can't get an accurate read of combustion mixture because the O2 upstream is reading askew, so it's either feeding ECU bad info about the mixture, causing the code, or ECU is getting bad info and feeding too much fuel into the cylinder.

Although, knowing the valve covers were done, they may've also effed up something with the fuel rail and/or fuel hoses to the passenger side, so that shouldn't be ruled out as a possible cause.

 

Nah, it's just one code. The one circled. The others are just "related", as in, similar codes that can pop up in tandem, or in lieu of - that's what was so damn confusing to me, but @KNABORES had it figured out:

​

 

The only code that appears to have been pulled was the P0174.

The rest of those are just on the info sheet as “related codes”. Dont go chasing waterfalls

 

I mean, I know TLC and all, but ... I didn't realize the rip-off until later in life...

https://www.youtube.com/watch?v=L0Px9QddbIg​

 

Here's google's answer. I'd start with the highlighted ones

The P0174 engine code indicates that there is an issue with the air/fuel ratio provided to your engine. Unfortunately, there are several reasons for this, ranging from air leaks and fuel injector issues to malfunctioning sensors. So it’s best to take it to a mechanic to get a professional diagnosis. The following are the most common causes of the P0174 code.

• Faulty mass airflow (MAF) sensor
• Blockage in the fuel filter and fuel injectors
• The fuel pump is getting weak
• Weakening fuel pressure regulator
• The vacuum connector or PCV line may have cracks or damage
• Defective oxygen sensor
• Issues with PCM
• Leakage in the brake booster

 

Just to be clear, ITS NEVER THE FUEL FILTER!!!

 

Welp, very happy to see the all-knowing Google agrees with me on MAF, fuel pump/delivery, and O2.

But just to eliminate that list in no specific order...

• It's almost never the MAF unless the problem is on all banks/cylinders
• Same ^^ is true with fuel pump, or fuel pressure regulator if the problem is on all banks/cylinders ... and it's never the fuel filter
• If the code is limited to one bank/cylinders (one side of engine) only, it could be blockage of the fuel rail for that side of the engine or it could be the upstream O2 for that bank/side
• Vacuum line/PCV/brake booster leak seems like a stretch, maybe this was only included for other vehicles
• PCM/ECU/ECM or whatever you want to call it, I might expect it with spark problems, but not fuel delivery limited to one side of the engine, given how the injectors are wired zig-zag-like

I'm going with faulty upstream O2 sensor, passenger side bank. But that's if and only if there's no obvious evidence the shop screwed up anything related to fuel delivery to the passenger-side rail.

 

o2 sensors were been replaced about a month ago. Maybe its an ignition coil with oil on it? Sparkplugs replaced about a month ago

 

Maybe i'll just sell the old clunker

 

Here we go. What brand of O2 sensors were used?

 

Walker

 

Yep, sell the old klunker

 

I replaced the sensors thinking it would solve the problem, but it didnt fix the problem

 

lol

 

iunno what to do

 

Walker is not OEM. Throwing parts at these without diagnosing the problem is not the way. Pull codes. Address common fixes for said codes with OEM or OEM supplier parts. It matters. No Scamazon knockoffs either, counterfeits galore. A misfire occurs when conditions for combustion are not met. Too rich or too lean. No spark. No air. In your case, the entire passenger side bank is showing too lean, so not enough fuel for the amount of air entering. If you are interested in chasing it down, and have the know how to do it, it can be fixed. Otherwise, have a trusted friend mechanic, or trusted hired mechanic help diagnose the problem.

















or sell it to me for $50

 

Replace that with Denso. Out trucks hate anything other than OEM/Denso.

Also since your code is for bank 2, you can swap the sensor between sides and see if the problem follows the sensor.