6-8 mpg boost for a high mileage Prius

More inertia?

 

Can I borrow your foot please?

Just ordered new plugs and coils for my 280k Prius. I’m also at 34 MPG, but I suspect it’s dropped to that level due to the new tires.

 

Sure can, let me find a machete.

Mine is a special case, I removed just about everything; no backseats and only 2 things in the back is the spare with tire tools riding on 185 width tires.

 

lol hardcore! A few hundred pounds yields 65MPG?

 

Add to your quotes?

 

I’ll be darned the OP was right. It’s only the first tank, but since changing my plugs I’ve gone from the Wth 34 MPG to 39 so far. Can’t wait to see if the coil packs boost those numbers too.

 

It turns out I spread some misinformation earlier about the misfire margin. It is a number the ECM is constantly recomputing while the engine is running, and its normal range tops out at 100. Whenever the engine is not running, this PID sits pegged at 127 (which is normally not a valid value for it). So it's no use to just go ask "what's my misfire margin?" and get a single number, which'll just be 127 if you're asking when the engine is stopped.

It is more useful to datalog and graph the misfire margin, over a short drive that takes in various driving conditions. If you're using Techstream, you can graph several things at once, like coolant temperature, RPM, engine load, EGR %, and misfire margin, and look for where the margin gets lowest, and what the other engine conditions were at that time.

For what it's worth, misfire margin wasn't new for Gen 3; I checked in the Gen 2 repair manual and it's in the Gen 2 data list also.