I'm hesitant to even write this post because I'm pretty embarrassed that I let the maintenance on this truck ever get to this point.
I've already spent the last few weeks searching the forum and a couple of other resources, including my FSM for what's wrong and what I can do about it.
I'm willing to learn, but inexperienced other than working on motorcycles. I've managed to do quite a bit of my own work on my bike with the help of a Yamaha forum and some good write-ups.

Background/Stats:

• 99 Tacoma 4WD, 3.4L SR5 TRD
• Purchased used 10 years ago with 109K
• 222k miles now.
• Regular oil and ATF changes, but that's about it other than a can of SeaFoam in the fuel periodically.
• Downstream O2 sensor replaced shortly after purchase.
• New belts (fan/alternator/etc) with new AC compressor in 2015. Done at shop once I realized I was out of my depth.

Current Issues:

• Timing belt - This may have been done prior to purchasing it, but I'm not confident of that fact. (Already bookmarked the sticky for this one).
• Pinging/Knocking/Preignition? - This is my best guess based on a couple of youtube videos that recorded the same noise.
• Battery went flat over the weekend, so it erased the codes that were being thrown out. I don't remember the exact code, but it was for a bank running lean. I'm hoping it'll throw the code again so I can get the exact one to update with.
  • When the new battery went in, the engine ran like garbage when first started from cold for about a week. Heavy stumble when accelerating from a stop unless the gas was being feathered. That went away - I'm assuming that the computer adjusted the fuel/air mix to compensate for whatever is happening to cause this.
• Exhaust Leak/Rattle - There are several places where the exhaust sounds like it's leaking/rotted away. Super loud from outside the truck, and the rattle only occurs around idle.
• Drive Train vibration - At certain speeds (35-38 and 65-68) there is a noticeable, rhythmic vibration that will rattle the entire vehicle. It pulses rather than being constant.
• Brakes - This is a dumpster fire. I've replaced the rotors and calipers several times, and within a week the rotors are warped and its like bringing a paint shaker to a stop. I tighten the lug-nuts with a torque wrench to make sure I'm not over-tightening them, but it doesn't seem to make a difference. E-Brake doesn't work because the bell crank is totally rusted over. The ABS light comes on periodically, and if I happen to be applying the brakes when that happens, the ABS kicks in. While it's illuminated, the ABS system doesn't function.

It's so much to do that I'm pretty overwhelmed. I'm trying to prioritize and gather the tools that I need to do everything. Unfortunately my family is also outgrowing this vehicle, so I'll likely end up selling it within the next year or so.

Is it worth it to do all of this just to turn around and sell it off? If it's worth doing first, I'm probably going to have to do it in stages due to budget constraints. Any suggestions on which things would be easier to do together? If I have to do the engine work in two stages, I'm assuming that the knocking/pinging is the more pressing issue to deal with. Basically, if this were your truck, where would you focus your energy and limited funds first?

Thanks ahead of time for the help, and sorry for the rambling post.

 

I vote you sell as is. With reasonable truth in advertising. Spending to fix all your laundry list of problems is not likely to net you much profit, especially if your truck is rusty.

 

I kind of figured as I was writing all of this down that just selling it as-is might be the best option.
Truck has some rust spots between 1/4 & 1/2 of an inch on the hood due to rock chips. Clear coat has failed on all but one door, and that one is starting to fail too at this point.

Are there any of these things that sound like they would return on their investment? The knocking/pinging/power loss issue is the one that I figure would be most likely to scare off a potential buyer.

 

Certainly a thorough tune-up couldn't hurt It might address the pinging.

 

Yeah I agree, I think you should sell as is. It doesnt seem like its worth the effort

 

That's mostly what I'm trying to figure out. I'm not very experienced, but willing to try. What should I be trying to take care of in a general tune-up? With how many problems there are, I'm not even sure where to start. Clean MAF sensor and put in new plugs/wires? Try to pull the injectors and clean them? I haven't looked into how involved of a job that is yet.

 

Hey Jr, how about spark plugs, wires, maybe even coil packs? might be time for the upstream 02 sensor? Clean the mass airflow sensor or replace. Idle control valve may need replaced. Got one on ebay for my sons t100 for $38 and also got oem mass airflow sensor for same price on ebay. What kind of rotors are you buying? I paid a little more for drilled and slotted rotors and my warping issues went away. Your drive line vibrations...have you checked your u-joints? Also, if im correct, you should have a center support bearing on your rear drive shaft. My 03 does. Mine was shot at 100,000 and replacing it really helped my drive line vibrations. The e brake could be a issue also. make sure it isn't froze up on the mechanism in your rear drums. to the point where it never completely released and is pressing out on rear brake pads. the rattle in your exhaust sounds like it could be a loose heat shield All in all, if you can do these things yourself. it shouldn't be to costly to get it running decent again.

 

You can learn a good bit watching YouTube videos. Many there for our 3.4L Tacomas

 

I wouldn't touch injectors till you try all the other things first

 

Thanks for all of the help. I'll get my to-do list in order.

 

My ABS system just ˟˟˟˟˟ the bed 2 days ago and caused me to get in an accident (nothing terrible), but I didn't want to put up with the ABS randomly coming on anymore so I just pulled the fuse out. Yes, my ABS light is on, but I don't have to worry about losing 90% of my braking power out of nowhere if it rains. This could be something easy (and free) for you to fix if you don't mind not having the ABS work. Also, check out what @djohn24 is saying because doing those things can completely transform the way your truck will drive. The stumbling could have been from a bad upstream o2, clogged fuel filter or injectors, or a bad fuel pump; minus the injectors you could easily replace those parts for under $100.

 

If pulling the fuse will keep it from sensing a fault and randomly kicking in, I'm on it. I'm hoping it'll kick that CEL code again so that I can get a better idea of where to start, but new plugs and leads are probably the first step. I replaced that downstream sensor myself, and It was rust-welded to the exhaust. I'll be taking a peek at the upstream one tonight after work.

 

Sounds good! And yeah do all the plugs/wires along with cleaning the MAF, throttle body, and IAC at the same time, doesn't take long at all and very easy. Also, the fuse for the ABS is held in by a screw on the underside of the fuse box in the engine bay. If you try and pull it straight out, it will not budge.

 

Your vibration is most likely the driveshaft center bearing.
Common taco problem.