I bought a 2010 Prius with 160k miles on it three years ago, currently ~ 210,000 mi. When I first got the car I got 44-46 MPG (I live in the mountains, but I would sometimes get 50 or a little better when going down into the Central Valley or Bay Area). I now am getting 35-38. I have been reading the forums and have conducted the following: Replaced hybrid battery with a new one from Greentech Auto in Sacramento Cleaned intake manifold, EGR tube, and replaced EGR cooler with a used, clean one Replaced PCV valve replaced MAF sensor Run BG 44k fuel injector cleaner about 4 times (this causes a 1-3 MPG increase for the treated tank then goes back down) I also had significant problems with oil consumption which I believe is to do with clogged piston rings. Every time I change my oil I run the BG oil cleaner for 10-30 minutes. This has dramatically reduced oil consumption and I went from burning a quart every 1,000-1,5000 miles to now only burning about half a quart to a quart over a 5,000 mile oil change. Don't know if this is relevant information or not. In the future I will also be running Valvoline Restore and Protect to try and help address this issue. I have also replaced the tires with not hybrid specific tires. I am aware that this may affect the mileage a little but I didn't notice a large drop from when I got them. It was getting mid to high 30s before and after the new tires. Not sure how much this matters. How can I get back up to where I was when I got the car? Should I check check compression? See if the injectors need a cleaning or replacement? Appreciate any insight. Cheers
you can clean the throttle body get a free load test of the 12v at most auto parts stores, and I've read that oil burning can clog the cat, but idk how to check it, or if it can affect mileage. make sure tires pressure are good. are the air and cabin filters clean? sparks replaced at 120k?
Thanks for the reply, I appreciate you. Guess I forgot about doing some of this stuff, but I cleaned the throttle body, it has a new battery as of a year ago, air and cabin filters replaced 1 year ago, spark plugs replaced 20k miles ago. I keep tire pressures at 35-40 PSI. I would think a clogged cat would show a code? I've seen that issue on mine and other's cars and it's always thrown a code. Only code I've got is for TPMS sensors and sometimes a vacuum leak code shows up but it doesn't stick around for long and always goes away shortly.
Was that traction pack a rebuilt or did it have actual NEW batteries in it?? When you replaced the pack, was it throwing codes??? You can verify traction pack condition by running the Dr Prius app. The traction pack needs to be on it's "last leg" or barely functional to throw codes. Lower mpg is the first sign the pack is going bad along with faster than "normal" discharge and recharge cycles. The CAT getting plugged-up is another concern. The oil burn clogs up the CAT filters and increases back pressure on the motor. Equivalent to stuff a potato in your exhaust pipe, forcing you to burn more gas for less power. Not that you'd notice less power in a Pruis, since it's a slug to begin with. Those are the primary things I would look at and start saving money for a replacement CAT, since that oil burn rate is going to kill it sooner or later. You may also want to invest in an ECT gauge, so you'll know when your pushing your motor too hard. This should help you side-step a head gasket repair and let you know when that electric water pump is getting lazy and needs replacement. The temperature lamp doesn't light-up until your 248+F, while normal operating temperature is around 185F-210F even in 100F weather running the AC. Vacuum leak codes will cause you to fail smog; I'm assuming your actually speaking about EVAP codes, because that'll show up on your CEL and could be as simple as a gas cap seal or intermittent/sticky solenoid. You'll need to hunt that down and repair it before your next smog check. Hope this helps......
