Air Inject, Squeal, Acceleration, and then Some

Welp, let’s start from the beginning.

8/31/23

Let me preface this by saying this may be a little long and by no means am I a "Car Guy". I'm more of an electrician by trade, so there are a few dumb mistakes I have made in this process.

Current stats of the car - Essentially stock 2015 SR5 4WD @ 112k miles with Michelin Defender LTX 265's.


Recently, last week Thursday, I was driving home from work and out of no where upon accelerating on the freeway the Runner didn't want to go. At this point, there was no check engine light. I got out, checked all the wiring was where it was supposed to be, and ensured everything was plugged in. Restarted the car, and it stayed sluggish. None of that initial kick when you go to accelerate. My RPM's would go up to about 2.5 - 3k, and would gradually work its way up to highway speeds.


My original thought was misfires, so being the idiot that I am, went ahead and replaced all 6 spark plugs with the Denso 3417 SK16HR11 Iridium Spark Plugs. This was done without using an OBDII, because well, I'm an idiot. After taking a few hours and replacing them, started up the runner and the check engine light and TRAC OFF were on. Instead of reverifying everything was good to go under the hood I took it for a drive around the block and noticed the same conditions as before, but maybe a little worse. Upon accelerating to 30mph, RPM's went to around 2.5k and then dropped down to 1k. Got back home and called it a night after ordering an OBDII on Amazon.

The next morning I went out to the Runner, ran the OBDII and the only code received was P2438 (Secondary Air Inject, System Air Flow/Pressure, Sensor Circuit High Bank 2 is what reads on the scanner). After some googling, checked out the Secondary Air Inject Pump, and saw that I had forgot to plug in the wiring that goes in to the Air Pump Control Valve that is on the drivers side. After plugging that back in, the check engine and TRAC OFF lights were off so I thought I was in the clear. Took apart the Secondary Air Inject and made sure it was clean, and that there were no loose filter parts. Started her up again, and took it for a drive but to no avail, still seems sluggish. Slow to get up to speeds, with various RPM changes in between and while idling I'm at about 500 - 600 RPM. ECO Mode seems to wig out as well while driving, but I think that's because after unplugging the battery the system doesn't know what's ECO and what's not, not sure.

Drove it today on the highway and the overall feeling is sluggish and slow to get up to speeds. Can’t seem to get more than 13.3-13.6 MPG as of late.

Other problems:

June 30th I got my oil changed because I don't have the tools or the space to do it myself in my apartment complex, and believed everything was fine when pulling in. After the oil change I noticed a squeaking that wasn't coming from the brakes while driving. Within the last 2 weeks, the squeaking has gotten considerably worse. When driving normally, 30mph and below, a high pitch squeak is heard and it is easily heard in my complex's parking structure. When going around the structure it is very noticeable, as well as driving on surface streets. It is heard when driving on bumpy areas, and on more or less flat roads as well. Not sure what this could be. Also of note, doesn’t seem to occur upon initial start up of the Runner, after some driving around it’s pretty prominent.

TPMS indication on the dash, tire pressure is ok.

Services done to the Runner-

@ 100k:

* Serpentine Belt
* Spark Plugs
* Transfer Case Oil Change
* Front Diff Fluid and Servicing
* Rear Diff Servicing
* Transmission Flush
* Michelin Defender LTX M/S 265/70R17 installed on stock wheels

Regular Oil Changes

I replaced the clock spring myself at ~100k due to the horn not working when the steering wheel was centered. No longer an issue.

I have a Secondary Air Injection Pump on hand now, along with the Filter "Mod" to replace the mushroom cap and I intend on replacing the pump.

9/5/23

Installed Prinsu Roof Rack

“Broken” roof rack thread bracket (plastic bits) drivers side rear, fixed by taking down the inside headliner and holding the bracket in place. A new bracket has arrived, and will be installed. When putting the roof rack back on, I intend to use Permatex 80050 Clear RTV in place of regular non hardening silicone.

9/7/23

I arrived at work and popped the hood just to check things, noticed that the bolts into the drivers side air injection check valve above the spark plugs were not tightened down all the way (another smooth move on my behalf) I tightened those down, ran the OBDII and there were no codes shown, all green. After work a buddy who owns and works on his Toyotas/Lexus’ came out and checked the engine as well, while revving the engine unplugged the MAF Sensor and threw the various MAF sensor codes associated along with the check engine light. Plugged it back in, no check engine light. But the codes remained, cleared the codes, now just the P0102 “permanent” code is present but “green check mark” on the OBDII. Good indications.

At this point, the 4Runner still seems sluggish, and not very responsive to throttle and acceleration. RPM’s sitting around 2-3k normal freeway speeds, go up when accelerating, and I can feel the gears shift as I accelerate. Squeal comes and goes, but it is heard almost every day. I feel light vibrations when driving that don’t seem too out of the norm, but I don’t believe it feels like it used to. Not sure what all of this could be, and any help would be appreciated.

 

Sounds like it’s in limp mode.

 

Definitely was after I left the check valve unplugged, but isn’t any longer. Passes 3k RPM, and I can feel the gears shift.