Indeed you sound very well informed. Thank you for your detailed approach.
Coolant level is fine in both the reservoir and the engine block. Some details were omitted as I attempted to summarize in the original post; generally against my normal methodical way.
So here’s the QUESTION: The Solara has been checked multiple times for stored trouble codes (incl. a transmission shop). Twice prior to purchase in Texas, and several times since returning to Denver. Do I understand correctly, your opinion is the first two sensors identified, if defective, WILL NOT GENERATE TROUBLE CODES stored in the car computer ?
1) coolant temp sensor
2) mass air flow sensor
It’s unlikely there is a vacuum leak, though regardless, my apologies for not having yet performed this test. In the past, I would check for vacuum leaks with water in a flower plant spray bottle. Small amounts of water change the fuel-air mixture and cause a rough idle. But have not yet verified from a trusted mechanic if water can damage engine air “intake side” components like the mass air flow sensor. I understand professional mechanics prefer propane gas; small amounts increase engine speed. But something about introducing a potentially explosive mixture into the engine compartment causes anxiety. Not enough experience I guess.
My intent is to purchase sophisticated software that includes the Data Logging feature with dedicated software specifically for the Toyota 3.3 L V6. The diagnostic software capability is very close to that of the Toyota dealer. An “interface module” plugs into a notebook computer USB port (same as the dealer). Data is stored on the hard disk drive.
Reviewing sensor signals (updated several times a second) for just the first two minutes during the warm-up problem, hopefully, specifically, identifies out of spec. readings. In colder winter temperatures, reduction to 1,000 rpm idle takes over 2 1/2 minutes. Considering the unusually low mileage, the drive-line exhibits more “play,” shifting from Park to Drive. No doubt, from the previous owner shifting the transmission into drive at 2,000 rpm.
Mechanical experience ? Probably advanced, but too slow and methodical to ever make it as a real mechanic (except part time in college . . . infinitely better than the usual minimum wage positions). Having run several cars over 220,000 miles, it’s normal to “invest” in factory service manuals, occasional specialized tools, and now, computer software. Historically, have performed all repairs /maintenance except wheel alignment/balance. With a better income, I would look forward to hiring a mechanic.
Regardless, really appreciate your conscientious, detailed information.
PS: Hope you receive this post. Originally, I was able to see only your name, but unable view your detailed reply.