You have lost me Wanderlost, but does that mean the GPS receiver in the vehicle cannot accurately calculate speed over the ground, at least to the degree necessary to calibrate a vehicle speedometer?
Having worked with the military capabilities of GPS in regard to aircraft, I am aware it is very accurate positionally. One would think the civilian variant could at least calculate accurate MPH of a vehicle traveling at a relative snail's pace.
Very cool, we have similar backgrounds. The most modern commercial transport aircraft use ground based augmentation systems for GPS position error. GPS speed is only used in conjunction with high integrity inertial navigation systems for back-up airspeed in an emergency.
How is this done? A gadget one attaches to the OBD plug? Recommendations?
Yes, usually someone releases an OBDII programmer that can do this and some other car specific functions. Something like this: ECRI Jeep Wrangler Calibrator - JK JL JT - Tire Size, Gear Ratio, TPMS
I think they also went to 0-20 weight oil and lowered cross bars (making them less useful for attaching sky boxes) to improve gas mileage. I would love to see a 5 or 6 speed manual (makes it more theft proof), but I don't think that's going happen though some of the new Tacomas will have 6 sp manuals I read.
Thanks carpool. Not want I wished to hear, but no surprise.
I get why Toyota doesn't even allow any form of ECU modification/recalibration, it's directly related to odometer reading so messing with it is tantamount to altering odometer. If one can easily set the tire size parameter, it'll make it too easy for the bad actors to cheat odometer by "selecting" smaller tire size and under register the true mileage.
With my 4Runner now, the cruise control is just not very pleasant unless on relatively flat roads. It is a big, heavy box that has just enough power. So anytime it is loaded or on a grade or has draggy things attached, it has no choice but to kick down to 4th or 3rd gear to maintain speed. And it doesn't want to just kick right back down after upshifting, so it holds that lower gear over the crest of a hill where I'd normally have let off the accelerator. The vehicle can't see that we are cresting a hill. It's much more pleasant to just drive without cruise control on anything hilly.
I hear you about the cruise control. I find my gas mileage improves when not using cruise instead using the accelerator to minimize downshifting on steep hills. I figured Toyota would have a TSB issued for the constant downshifting and exceeding speed limits using cruise control. I look forward to test drive reports in the near future. None so far...
Dream on re a TSB. It is the nature of the beast. Our 2005 4Runner had this issue. Pre-2024 Tacomas also have the "hunting" problem. I wonder if the current generation of 8 and 10-speed tranny's also have this malady? I suspect so.
The reason it is so clear on the 4Runner is because the steps between the gears are very large. At 70mph, your choice is to be at 2000RPM in 5th gear, 2500RPM in 4th gear, or 3200RPM in 3rd gear. If the engine can't make enough power to pull the hill in 5th or 4th, it has no choice but to jump down to 3rd gear. On an engine with a 5800RPM redline, jumping from 2000RPM to 3200RPM feels drastic. The 8 and 10 speed transmissions should have the ability to make small steps down more likely landing on a gear that "fits" better and, as I mentioned above, they will have the ability to lean on making boost or pulling energy from the battery to fill some of the engine's power gap in the higher gears. I think it will be more invisible thanks to the multi pronged approach.
