New Owner of potential problem

Hello all! New here, new to Toyotas.

I recently just made a purchase of a 2010 Sequoia SR5 4WD with the 5.7. It has 295k on it. My mistake was buying the thing with all the Christmas lights on! Flashing CEL, flashing VSC, flashing 4lo. Codes are p0300, p0302, p305, p0352. I drove it 1h 45m back home with no issues. Truck ran relatively snooth, except it would not pull full power when floored. It maintained highway speed, as long as you didn't floor it to accelerate past someone. You had to ease into that acceleration. The prev owner said that their "trusted" mechanic told them they needed the VC gasket & tube seals changed.
Immediately upon buying the truck, I performed the valve cover gasket change along with spark plug tube seal change on both sides. Looks like the driver's side was done recently, passenger side, never. And I can see why! New iridium plugs.
Back to the codes. They were there before the job, they're there now. I bought a new Denso coil, put it on #2. Same codes. Moved it to #5, same codes. I randomly swapped coils to different positions, same codes. Truck runs a little rough now as it hadn't before. It surged on idle with AC on, as it did not do that before. I cleaned throttle body, intake tube and MAF sensor.
Something else struck me as odd. If I completely unplug #5, I get p0355. Plug it back in, p0355 goes away, but p0305 remains...

Please, any ideas?

 

Well, I'm sorry for 2 things. 1 being I'm sorry you are having these problems. 2 being I can't help you. But I can tell you that you're in the right place to get some help. Send "Shifty" a pm. Most of us here will help where we can, Shifty is kind of the sight guru for Toyotas.
Welcome from TN!!

 

Thanks Corndog123! From TN as well.

 

Welcome from LA (Lower Alabama)! Yes, @shifty` can most likely help you out.

 

Two things:

1. I know virtually nothing about 2nd gens, or the 5.7L platform
2. I don't offer support via PM, please DO NOT ask people to PM me, ever (a tag in a thread us normally sufficient to get my attn)

All I can tell you here is this, and I realize it's generic output:

• Flashing CEL = major issue ("stop driving") and is common in misfire events
• P0300 is random misfire, cylinders 2 and 5 are on opposite banks, but p0352 may be the better direction to follow
• If you can get a copy of the FSM (factory service manual) online in PDF format for a truck around your year, they'll give you diagnostic steps for p0352
• Track down p0352 cause first - sounds like you have a possible wire chew/wire pinch/wire nick situation.
• Don't foget, this could be a timing issue, IIRC the 5.7 uses timing chains, and if it weren't for the p0352 code, first thing I'd do is verify timing (but I'm not sure I'd bother in this case).
• If it weren't for the p0352 code, I'd also be telling you to do a compression/leakdown test, since the 5.7L have far more head gasket issues than its 4.7L predecessor

Grab a PDF copy of your FSM. Run through Toyota's diagnostics for the p0352 which will be searchable in said PDF. It'll tell you what circuits to check. OR take it to a dealer and pay them for 1-2 hours of diagnostics so they can tell you what's wrong. I'd only trust a dedicated Toyota shop - private or dealer - to tell me legitimately what's wrong.

 

I appreciate your input nonetheless. Thank you.

 

Oh, and I'd elaborate/add.

It's weird your misfire is on opposite banks, and I meant to say that.

If I recall Car Care Nut's breakdown on the 5.7L head gasket failure issues, it typically happens on the head gasket for the middle two cylinders, but I'd be highly skeptical a head gasket would fail on BOTH banks (logically speaking) at the same time.

So I'd really be leaning into this being (first and foremost) in the wiring. And remembering the issues my dad had with his 2.5 gen with rodents, if there's similar issues with the 2nd gen Sequoia, you may want to verify the wiring to your ECU, and wiring in general. Rodents love to chew wiring.

I know on the 4.7L, the wiring order on the coil packs is 2-3-5-8, 1-4-6-7. If you look up the 5.7L and find it's the same diring order, and you have a misfire on 2 and 5 (p0302, p0305), that'd have me honing in on the p0352.

But anyway, The LC shares the same engine, IIRC, and here's a breakdown of the diagnostics section for P0352 for you straight out of the LC's FSM which should get you started on diagnostics @CommieLS3: https://charm.li/Toyota/2010/Landcruiser V8-5.7L (3UR-FE)/Repair and Diagnosis/A L L Diagnostic Trouble Codes ( DTC )/Testing and Inspection/P Code Charts/P0352/

Note what that says about the coil #1 and coil #8 early on. You may want to try swapping coil 1 to 3, and 8 to 6, if that's a thing.

 

Thank you. TBH, after replacing the coil & moving it around & getting same codes, I was thinking electrical. Then, my mind went to one of the worst outcomes, the head gasket. I'll take a look at that thread and see how good my Russian is (looking at & understanding) electrical diagrams

 

If your SUV has the 3UR-FE in it, all odd cylinders are on bank1/driver, and all odd cylinders on bank2/passenger.

I'm not saying it's "impossible", but the chances of head gasket breach which impacted both banks, outside of a major overheat event which would probably be more-catastrophic to other components (in my layman opinion), I'd be shocked to see that.

But that's just my opinion, and you know what they say about opinions ... (kinda like assholes, everyone's got one, and they usually stink)

 

I sincerely apologize from the bottom of my heart. It will not happen again. That I can promise.

 

Oh dude, not sweating it!

 

Shifty, You may not know as much about the 5.7L models as you do about the Gen 1's, but you still know more than the vast majority of us!

 

Just to give everyone and update:

I took the tree to a Toyota specialist. No sense in throwing money/ parts at it. It was #6 coil. When they called me and told me this, i asked if they were absolutely sure & they were. I told them what I was getting and they basically told me it could've have been my scanner. Either way, fixed & running absolutely great. On a 5 hour road trip as we speak!

 

Fantastic! I'm glad you're running!