I do not believe in coicidences

Hello,
I am new to the forum and am seeking advice on my 1997 V6 SR5; it has 284,000 miles. Sorry about the long story but too many things all at the same time; my life story.
About 6 months ago I got a check engine light; first time ever!
So we understand each other, I am the daughter of a heavy equipment mechanic who insisted that his children be able to do all of the maintenance and standard repairs on the vehicle before getting our driver's license ~ Thank you Daddy! I was also an Army wife for 30 years, so managing on my own is par or the course. I take exceptional care of my vehicle. I live in the country, by myself, 30 miles from the nearest gallon of milk. This vehicle is my lifeline.
Immeduately after getting the check engine light I took it into a local shop to have the code read, they said it was the catalytic converter. As this was the height of COVID, getting it repaired was questionable, at best. I was advised to run a couple of cycles of Cataclean through the system. I filled up with super and ran two bottles through. Since I only drive about 100 miles a month, this took awile; the check engine light went out. I asked what were the signs that the system was going to fail. They said running rough and drop in gas milege; I always fet 18 mpg and it's never leaked a drop of oil or fluids. Late one night, in the bad part of town (of course) it got what I call the "chugga chuggas" and died. What I figure an engine would act like if it sucked up a chunk of something from the gas tank and needed a automotive version of a heimlich. I let it sit for a few minutes, it started and I drove home.
I figured this was my warning and called my favorite Toyota dealer to see of replacement Toyota parts were even available for the converter. I was in luck; yup they could get the parts so I started to make plans to get repair done. Because nothing ever comes easy, in the mean time my USPS driver forgets to put her van in park and it rolls into the driver's rear bumper. As I was taking it in for the converter, I arranged for the replacement of the bumper at the same time.
They did the converter, annual maintenace and safety inspection first, then took it to their body shop to replace the bumper. I picked up my vehicle and half way home the check engine light came on again. I also noticed that the blinkers were not working correctly (acted like a burned out bulb) and the moon roof would not open, I can hear motor turning but does not open. As it had passed the safety inspection, this had to be a result of the body work on the bumper. I contacted Toyota to let them know, planning on bringing it in the next week. I had to go into town (15 miles) in the next couple days. It's hot and humid as hell outside. I park outside a business, when I come back out maybe 10 minutes later, it won't start, it will crank but will not turn over. I do all the things you do if it's hot outside, waited half an hour, still won't turn over. I had it towed to my home, let it sit over night, then AAA'd it to the dealership the next day after it failed to start even after a good night's sleep; my 4-Runner, not me.
Toyota's conclusion was that there was a pinched wire from the bumper replacement and the wiring harness to tow a trailer (aftermarket add) should be removed; likely causing blinker problem. The fuel pump and sending unit needed to be replaced, the likely cause of not starting. Another $2000ish, I pick it up, blinkers work, no check engine light but the moon roof still doesn't work. I was told that the cables were binding and it would be $1800 if parts could be located. ????? Really confused because it only stopped working when bumper was replaced and there was a wiring issue. I drove home and noticed that the wiring for trailer had not been completely removed. I'm not certain what they did, my understanding was that they were returning it to how it was before harness was installed. If they did that, there should be no wiring by the hitch receiver.
A couple days later, my niece is driving on the interstate and it dies, at speed. She is a new driver, so doesn't have enough experience with explaining what happened. Basically engine quit, all power systems failed and she managed to safely muscle it to the shoulder while coasting; AAA back to dealership.
New service manager, seems nice but made the mistake of telling me what I do and do not want ~~
He said that they went over over the vehicle with a fine tooth comb and could find nothing wrong, there were no error codes and it even started right up for them. This sounds like a loose wire type issue to me. Jiggles loose, vehicles stops, won't start. After being jostled for 70 miles on the back of a tow truck, wires are again sending enough signal that nothing glaring is wrong. I mentioned the wiring harness and asked if there was anything that could be loose. He said he didn't know, but one should not have anything to do with the other. I explained that I was told the entire harness would be removed and the system returned to "factory." He told told me that I didn't want to do this because then I couldn't tow at night. I "calmly" explained that if that wiring had a short, and my engine kept cutting out, it didn't really matter if I could tow or not. I insisted that the entire harness be removed and checked for good signal. (I can always put it back later if that solves the problem.)
I picked up my vehicle, no problems were found.
Yesterday we had to drive to D.C. It's about a 2 hour drive and again, hot and humid as hell. On the trip up there I drove, engine seemed fine, sounded fine, brakes were mushy. On the way home my niece was driving, I was dozing. About 30 miles outside of D.C. I turned on the ECT and turned the O/D off for her. I am very familiar with that section of road and the hills pull hard on the engine, especially when it's hot and traffic is heavy. I went back to my nap. About 10 minutes later my niece is freaking out because the engine is revving by itself, tachometer bouncing between 2500 and 4000 without her pushing on the accelerator. I quickly turned the ECT off and the OD back on and it seemed to settle down. We took the next exit and pulled into the parking lot, turned off the ac and let the engine idle so I could watch/listen to the engine, heat and tach gauges. The tach kept jumping between 500 and 2,000 then died. This after idling for less than 5 minutes. We let it sit for 30 minutes, said a prayer and turned the engine over; it started.
Other random observations ~ brakes are mushy, much softer than when this started. New brakes were installed 1 year ago, less than 5,000 miles. No brake warning lights, I haven't checked master cylinder for fluid level (currently lightening outside.) When I picked up my keys from the tray under the parking brake they were hot! Not just the usual warm but hot enough I had to put them down.
After reading several threads on this forum, it seems that something happens to these vehicles at about 280,000. Random issues with systems that do not give warning codes and it may be necessary to seek out members of secret 4-Runner lovers societies to isolate.
I am going to verify with Toyota that they changed the fuel filter when they replaced the pump. Seems obvious to me but . . . I will also ask about battery cables and grounding. I took some pictures but I don't see any obvious opens in wiring.
Any other suggestions as to where to direct mechanics would be greatly appreciated. I'll even add that it was suggested to me so they will get past the "grey haired, Colonel's wife" prejudice, and actuallly listen to me.
Again, the fact that the moon roof started acting up at the same time I develop other wiring issues just seems to much of a coincidence.
Thank you in advance!
Kym

 

My cat was replaced under recall notice. And rear springs. What was the code? Most common is the O2 sensor and I think you only have two like mine, but if it’s unburnt fuel the cat would really heat up, like from bad plug wires and such.
I would just caulk the sunroof at this point they will start to leak and rust/lock up.

 

25 year old vehicles will start to have a variety of issues, no matter the make.

The surging is probably the throttle body needing to be cleaned, or the IAC needs replacing, or the MAF needs cleaning, or the TPS is going bad. The engine computer is trying to hunt for the proper air fuel mixture and can't get it right, so it surges.

When were all the vacuum lines replaced? If never, they are hard as a rock by now and suspect.

The mushy brakes are probably related to bad or old fluid. A leaking line or cylinder perhaps.

Wiring needs to be checked for each issue I think but should not be related to the brakes and doubt it's related to the engine surging.

You really need a code reader. The check engine light is a worthless device intentionally created to give the dealer a way to rip you off. When it comes on, with a reader, you can grab the code and know what it's pointing to.

 

I’ve changed my air-filter 3 times in twenty years.

 

SR5 Limited ~ Thanks for responding. I don't remember what the code was. The mechanic was flaky; thinks that estrogen blocks one's ability to comprehend anything but shades of nail polish. ‍♀️ I should not have bad plugs, everything is maintained on schedule; wires, maybe. I was referring to fuel filter, not air filter. I'll have to crawl under when it stops storming and check to see if it's new.
As far as the moon roof; it is a valuable piece of machinary for me particular lifestyle. I live in the woods, 1,000 foot driveway. I use it to help me trim the trees back. Drive down the driveway, crawl out the roof, use pole chainsaw to trim overhanging branches, crawl back into driver's seat, pull forward. Wash, rinse and repeat.

 

Negsum, thank you.
I'll have the vaccum lines looked at. All the electronic parts you mentioned; IAC, MAF, TPS ~ would those problems show up on a code reader that a non- professional could purchase? I've thought about getting one but since this was my first "check engine" light ever, I hadn't done any serious research. My dad passed away in December so my "go to favorite mechanic" isn't available for advise any more.
Can you recommend a particular brand or model? I'm not so much concerned about price as I am function for my needs. I also don't want something that requires a semester of education to learn how to use. Straight forward, functional, reliable, reasonably simple is the goal.
I'll add flushing my brake lines to the list of things to do, I know it's been a few years, along with checking the master cylinder.
Got my Haines out . . .
Thanks again, enjoy your day.

 

Don't forget the LSPV when you do the brake lines! A lot of people ignore and don't bother flushing it, and develop problems they can't track down. Better to flush it out every time you do the brakes, as recommended by the Book.

I picked up a code reader for about $25.00 at AutoZone. Little thing, about the size of a pack of smokes. So far, it's been exactly what I need to get me pointed right when the CEL comes on.

Good luck!
Pat☺

 

Kym, if you don't want to purchase a code reader, most auto parts stores have them available and will come out and read them for you. I keep one in my Tacoma, and it uses blue tooth to my phone - which has an app on it that came with the code reader. Mine is a BlueDriver. (The brand). Once it is plugged in to any vehicle, it communicates with the car's computers and downloads whatever software it needs to accurately read the ECU and other computers and provides information on each fault it finds - some that might not turn on the check engine light. It sounds more complicated than it is, but it is fairly simple. I think I probably paid around $40 for mine.

Edit: I looked up the price of the BlueDriver now and it is $120.

 

Yeah, like was said...just source a $25 code reader. It will at least read the engine codes and clear them. The 3rd gen 4runners are not so complicated that a fancy expensive code reader is all that useful. I record the code and clear it...sometimes they never come back for months.

For those items I mentioned...sometimes, yes a code pops up. Sometimes no. For my 2002, I had bad engine surging with my AC on. I didn't get codes for months. Eventually I got an IAC code which is funny since the 2001-2002 do not have an IAC like your car does. But when I did get that code...I knew to start blaming the throttle body (the IAC, TPS are attached directly to the throttle body). I decided to just replace the throttle body as a new one from TOYOTA came with a new TPS and new Pedal position sensor and its internal motor, etc. It completely solved my issue.

So yeah, knowing the codes is really going to help you know what to blame.

For you, I'd replace the IAC, which is easy and cheap and clean the MAF and clean the Throttle body. I highly URGE everyone to use ONLY TOYOTA parts. The parts work the first time and work for decades. You can buy from an online TOYOTA dealer which usually discounts 20-30% from your local dealer. ALWAYS supply your vin when buying parts. All TOYOTA dealers, online or otherwise, double check parts against your vin and I have NEVER gotten the wrong part yet.

Luckily, there are TONS of youtube vids for cleaning and servicing the intake on these cars. Also, these engines went into Tacomas and Highlanders, etc...so tons of videos of people fixing them.