Update: 2005 6MT Sport w/149,000 miles on original engine
 

Running strong as ever.

Have only used conventional or blended 10W-30, 5W-30 oil (okay, sometimes 5W-20 during early years).

Have only done oil/filter changes at between 3500 and 5000 miles, coolant flushes/fills every 60,000 miles, brake rotors once, brake pads twice, brake fluid bleed and refill once, coilpack/plugs/wire changes twice, rear diff gear oil change once, two new batteries, ...let's see...

...had one problem with valve stuck open on manifold bank 1 that resolved itself after about 700 miles and never affected performance, a side passenger door lock actuator that stopped working for about 2000 miles then started working again by itself, and a issue whereby the 02 sensor on the cat came loose with a portion of the cat metal shroud that cost $77 to fix at a local muffler shop.

Original headlights (HID) and tail lights still work (never changed), there's no rust (not even rear wheel wells - which I clean regularly and apply Fluid Film and CRC Heavy Duty Marine to in fall, and also to frame rails with heavy spray into wash areas and at jack point areas) despite being driven year round in the snow belt.

Oh yeah . I've averaged about 20 mpg (280ish miles per fill) using mainly 87 octane in mixed driving (45% highway/55% city).

Compression test results?

NAP - Never had compression tested. This is now a 2nd car, but I dutifully drive it about 30% of the time now, year round, and never bothered to have the compression checked.

Forgot to mention above that Mazda replaced air bags, and much earlier on, I think in 2008, both the starter motor and original Panasonic battery for free under either a recall or TSB for weak start.

I also had a recall for fuel fill neck (?) done in last 14 months?

That's wonderful.
I too run 87, dino oil 5w30 and redline whenever. ~450km range mixed driving. Catless. OO & OE.

Honestly, the fascinating thing is that I haven't treated the 8 much differently than any other vehicle I've owned.

Yes, I have swapped out coilpacks/plugs more often than I would have in say, a Camry, and I don't short trip it often, and keep the oil full, but other than that, nothing really special as far as treatment, and no worse for wear.

We all wish for what you have experienced. Congratulations. Regarding 87 octane, I tried 85 octane ( in Colorado over 6000 ft elevation). Our premium is 91 octane. My car ran better on 85 than it did on 91. Engine was smoother with less vibration and seemed to accelerate a little better. Same gas mileage 18 - 19 average. So I alternated every 2 tanks. Then I tried no ethanol 88 octane and the car runs the best it ever has. Virtually no vibration which I judge by the gear shift when idling. Definetly better and smoother acceleration.. Now that is all I use.

Was waiting for the latest update to see if I had the last running 8 in Michigan. 126k miles here, pretty much the same as you. Only issue I've got atm is the TCS light is stuck on, but luckily I have a couple of months to deal with that one before winter shows up. I've thought of getting a compression test, but I've always said screw it and kept doing what I've been doing.

I'm assuming 10W-30 in summer, 5W-30 in winter?

Andrew, Delhi, Petscar -

Mainly 10W-30 in summer and 5W-30 in winter. I've used 5W-20, 10W-40, and some other viscosities, also, but mainly 10W-30 or 5W-30.

Also, almost always 87 octane.

Always awesome to hear about high mileage 8s. Do you use premix?

Good deal. I've usually stuck to 0W-40, but I may switch to the 5W/10W-30 approach, to tighten up the viscosity if anything.

I've only been brave enough to try 89, but I may try 87 since I've seen nothing wrong with 89 so far. That and the gas price jump from Canton to West Bloomfield has been annoying to say the least.

Some rotaries respond well with 87 some don't. I suggest you ease into it and experiment with a few 1/3 tank. If there are no knock detected, just keep lowering the octane. If you do a search, many FC RX7 owners run as low as 85 oct! I don't even know where you can find these.

I've tried every octane at least 2 back to back tankfuls at a time to verify the response. With 85 (87 octane equivalent at lower altitudes) my car ran better than 91 (our highest octane at 6000 ft elevation).

Then I tried No ethanol gas which was 88 octane. Holy Crap Batman.... My car is running so much better!!!! I would say it is running like new except I dont know what a new 8 drives like as I bought mine used

I would like to hear from anyone who tries ethanol free gas.

Here is a website to find gas stations in your state. This link is set to Colorado.
https://www.pure-gas.org/index.jsp?stateprov=CO