Truck with Neglected maintenance. Most of the work done now.

Let the pcm adjust over a couple weeks maybe, I did more less what you did and at first my idle was high but settled in after a minute. Cool wrenching

 

After replacing Bank 1 Sensor one (which was dead) I now have the opposite affect. It Idles pretty high but only in park. (1.5K rmps>maybe a pinch less at temp) I'm not used to how the truck normal runs as it's never been as nice, smooth and clean as this.

I also get a "running lean" code from Bank one Sensor one.

My evap lines are PRETTY rotted. MAF is probably wack (ill probably replace it but keep the old part to possibly swap back) To my knowledge "basic" Vacuum hoses are solid. Manifolds/Exaust needs to be inspected. Fuel pump could be tired at 256k miles.

 

Hmm I wonder if that should be plugged in?

Pluging it in fixed my idle to near regular levels but still not ideal.

I still get the "System to lean" code. I think it will be my evap system or MAF sensor.

 

Fun to read about your journey, thanks for posting! I'm driving a similar aged taco with 414k, 4wd manual. I'm new to trying to work on it much myself. But it's had good maintenance over the 23 yrs I've owned it. My 1st big job may be dropping the transmission in the driveway for a rebuild once we get a 2nd vehicle.
Yours will be in great shape once you are done and give you many years of service. Great work, and inspiring.

 

I can tell you are a young guy and new with vehicles, and like any young guy you dump tons of money on stuff you don’t need. Especially with first vehicles you fall in love with.

nothing wrong with replenishing many of the disposable parts. I personally would only recommend OEM, MOOG (with zerk fittings) or recommended aftermarket for steering parts. The knuckles, unless rusted through, are probably better better off stock than any Chinese low quality aftermarket. The last thing you want is to bust the flimsy metal on some hills leaving you stranded, however I don’t see that truck doing any suspension work in your area.

Typically the timing belt would be replaced any time it’s removed (unless it’s super new). So if he replaced the water pump I don’t see why it wouldn’t be replaced. Seeing as it’s sold as a kit usually.

As for rough running engine, I would have started with replacing the spark plugs and wires, cleaning the throttle body , inspecting and replacing vacuum hoses, replacing PCV valve, replacing fuel filter and air filter.
Nobody here is helping you not dump money needlessly which I’m not accustomed to seeing on automotive communities.
For the people that recommend a fuel pump, did you
Check the fuel pressure? With key in on position then while running?
Why did you change the O2 Sensor and to which brand? Electrical parts are important to get the right brand (Denso, NGK for plugs and wires). Also no need to replace your MAF unless you’re getting codes for it and completely stumped. Just clean it with MAF cleaner and reconnect the battery.
yes, some times you just need to reconnect the battery after doing major work
(You did unplug the battery to take off the intake manifold right?)
You need to do some real troubleshooting and not just throwing parts because that can just as easily cause damage or kill yourself doing steering and suspension work as a novice. The lack of real help I see for you tells me a lot about the mechanical aptitude I can expect to find here
You need to check steps A before you go to Step B. It’s good to find stuff out with a project to mess around with. You’ve certainly went above and beyond with f-ing around and finding out, not everyone has the second vehicle or lack of responsibility to be without a vehicle!
Get yourself a decent OBD2 reader to check the sensor data.
Have a mechanic mindset going into repairs, not be a YouTube part swapper.