I threw parts at my truck. Runs the same

Guys I need help. I know it’s a long read. But please help.
Bought a 2010 Tacoma TRD Off Road 1GRFE 4x4 back in April with 151k. Currently have 157k
When I bought it I noticed that it was kinda lacking power. It’s a really clean truck inside and out. Engine bay is spotless and almost all components look like they came from the factory.

Some of the symptoms I would get were:
-lack of power
-poor gas mileage
-weird fluttering/ticking noise directly in front of drivers seat in the engine bay while driving.
-reverberating vibration under load. Can really feel it only in the gas pedal.
-spark knock when I don’t use 93 octane
-sometimes the engine runs great and I don’t have any of these symptoms, but majority of the time it has these symptoms.
-my OBD says everything is working as it should. No codes, lambda stays around 1.00. LTFT and STFT stay around 0.0.

What I’ve done, and yes they were properly installed:
-Oil change/oil filter of course immediately, did another oil change after 2,000 miles.
-OEM fuel injectors/new plenum gakset
-OEM maf/ air filter
-throttle body clean/with new gasket
-OEM iridium spark plugs/OEM coils.
-pcv valve
-OEM VVT solenoids
-OEM vvt filters
-Toyota dealer did a fuel service for carbon build up
-complete coolant flush with OEM coolant put back in
-transmission/transfer case/ differential fluid changes
-dropped oil pan to check oil pick up and it was spotless. No sludge or carbon in the screen.
-checked the timing window on the timing cover and the tension plunger is not extended and is within spec.
-DIY Seafoam in the intake and a handful of different branded fuel treatments when I first got the truck.

*Brought it to a dealer 2 weeks ago for diag and they said “this year model was notorious for the cylinder 6 head gasket issue.” (The years were actually 2005-2008 not 2010) They checked cylinder 6 with a borescope and said they saw moisture in the cylinder head. They said it’s for sure coolant, however, cylinder 6 had the same amount of carbon as other cylinders, so no steam cleaning happening, my coolant level hasn’t changed in the 3 months of owning it, I haven’t even seen the slightest bit of smoke come from the exhaust. They compression tested the coolant system and said I’m slowly losing pressure, but even when they had the borescope in the cylinder and the system pressurised, there was no evidence of coolant leaking into the cylinder (i made them show me in person) My assessment for that is they were doing the typical dealer things to make a buck. My valve cover gasket is barely leaking around a couple of my spark plug holes. It will pool up just a little towards the threads of plug. Not enough to affect spark plug/coil contact at all. When they pulled the plug, the pooled up oil went into the cylinder and they tried to pass it off as coolant. Maybe I’m wrong but I feel like I would get other symptoms of head gasket issues like oil in coolant, coolant in oil, or bubbling coolant when cold starting.*

If you’ve reached this point, thanks for reading. I’ve had absolutely nothing positive to say about the mechanic shops around where I live. It’s just cash grab mechanics that will just throw parts at your vehicle to get the labor. Every time I’ve gone in they either say “nothings wrong” or they’ll hit me with “you need to replace ____part” even though it was already replaced and if that part was indeed bad, an OBD scan would tell me. That’s why I’ve resulted to this. Maybe I have no clue what i’m talking about and it’s just ignorance on my part. If any of you have any advice or experience in something similar, I would love to hear it. Thanks.

 

Just for fun, pull your upstream o2 sensors out of the exhaust and go for a spin. Sounds like your exhaust(cats) may be plugged.

there are more proper ways to check for a plugged exhaust but this is the down and dirty way.

Warning, it will be VERY loud

 

do a cylinder compression check and leakdown test.

While all the things you've done are good to do, most are basic maintenance and would not address your complaint symptoms.

 

No compression or leakdown test?

I would have started there

 

I second checking exhaust backpressure, classic symptoms of a restricted exhaust.

 

@Clearwater Bill @ZColorado just for transparency, by recommending doing a compression test, what do you think my issue would be. To see if I have a bad cylinder? Or to check if all cylinder compression is in spec? I went the route of just replacing a lot of things because they were probably due in the anyway. Thanks gents.

 

It would rule out that erroneous diagnosis from the dealer about cyl 6, and is cheap and easy to do.

I do like this plugged exhaust theory though.

 

Are you comparing your 2010 to other Tacoma's you've driven? Did you buy the truck figuring you were going to solve the power issues?

 

Yea I figured it just needed a decent little tune up due to the age/not having a clue what was done to it before. I’ve driven other 2nd gen’s before and I made a wild assumption that it just needs a little TLC.

 

Could potentially explain the Tacoma tick I’m getting? Back pressure causing exhaust manifold leak. Didn’t want to say that as a symptom because literally everyone and their mother has it.

 

The head gasket issues on the Tacoma 2nd gen 4.0L V6 (1GRFE) was corrected early-on in the run. Get a second opinion on it and proceed cautiously with this one, especially if it isn't losing coolant. The common timing cover oil seep was eventually corrected later in the run as well. My 2014 4.0L has no valve cover or other oil leaks or seeps at 140,000.

 

Taco tick as everyone refers to it is typically heard at idle, if it's ticking on acceleration it certainly could be backpressure/exhaust leak.

There's several ways to check for a restricted exhaust:

Backpressure gauge screwed into the upstream AFR sensor port.

Oscilloscope and in-cylinder pressure transducer.

VE test can be used as a guide but it's not a definitive way like the above methods.

 

Exhaust leaks sound a lot like ticks or knocks, so it's possible.

 

This sounds strangely similar to my truck. I kinda assumed it was normal. 2010 1gr- 153k miles.
That strange knocking on acceleration, stops when I reach a steady speed, worse when it’s cold.
Mine never revs above 3-3.5k rpms while driving, even when giving a good amount of gas. previous owner said it used to never go over 2k rpms but he ran seafoam through for a couple tanks and it fixed it.
Makes me wonder if my cats are restricted…

 

https://app.truvideo.com/v/ufaxkmEQ?s=S+qUq/vFPQvo4kfIF3hiU1dZOKV5hkfS

Looking to see what you guys think

 

I wish you had a video of what it sounded like driving
I’ll have to tap mine with a hammer see if it makes the same noise.
Seems like a smart tech though!