2010 150k mileage dropping to 25MPG Help.

My milage has been dropping fast the past few months. Hoovering at 25 before servicing. No major changes in driving or weather. Los Angeles area. 3 weeks ago I did brakes and rotors it was just time, it wasnt to combat milage. But regardless, No change.

Last weekend I did sparkplugs, PCV valve added an oil catch can, cleaned the throttle body. MAF. And intake. Cleaned the 3 EGR components, Pipe, valve and cooler. Changed the oil Mobile 1 0-20 high milage synthetic, changed engine and inverter coolant. The milage went up to 42 for a few days, now tanked back down to 28 today.

I had a few under a minute engine hot dummy light kick on, cooled and turned off before I could even pull over safely, it happened today even after the EGR system cleaning, So I am ordering a new water pump and thermostat.

I dont see any OBDII codes in torque even for the over heating issues. Im gonna test the 12 aux battery and traction battery with dr prius and see what I can find.

Shes running good, though seems a little sluggish, not as peppy as before. No engine shake or knocks. Smooth as silk. Just my milage sucks nice person. Wheel bearings all seem good when I did my brakes.

I am flippin stumped. Help.
More info from more OBDII testing incoming.

 

42/40 on TP and just chamged the plugs. NKG itridiums.

 

Seems pretty normal. Nothing catching my attention. Did a Dr Prius battery test and it came out at 55.39% life. All tests were good. No ECU errors or anything else.

 

Dr prius said traction battery is at 55.33% fair condition. No errors in ECU. 12v battery seems ok too need to get it fully charged and test again later playing with torque and dr prius for an hour it showed low at 11.1v but charging at 13.7. But I was going in and out of maintenance mode a lot so I was really punishing the 12v with head lights. Dome lights on off a lot.

I am so freakin stumped..

 

150k. I did have some oil burning, a quart every oil change or two.

No ECU errors or anything.

Im stumped. Thinking about trying new fuel injectors.

I passed smog in Dec. (California) asked if he saw any errors, said it was clean, no issues, smog results were perfect.

 

Tested again after driving that night and it sitting over night it was at 12.5 in the morning.

It was low cause I was having trouble getting in maintenence mode. Restarting over and over at night with headlights on and all that.

Tested again before going to lunch 12.6

12v seems fine.

 

Will test that tonight. And report back.

Im chanhing my water pump and thermostat today. Parts just arrived.

Debating new fuel injectors, or at least pulling to see if they look like crap.

I use seafoam in the gas tank every other oil change. They should be OK. If they look bad, Ill just replace em.

Im really just grasping at straws.

 

Yeah I was using in dash. Found a good spot to test under the hood in the fuse box, also tested on the battery itself. Dash shows 12.3. Showing 12.7 on my multimeter under hood and on the battery. Will test again in the morning letting it rest 12 hours and will report back.

I was gonna do my water pump and thermostat tonight, but my coolant isnt here yet, will do that in the morning and then take it for a hard run on the freeway and see how it does. Funny I get pump and thermostat next day, but 2 days for coolant.

If it sucks after a week, Im gonna try replacing the fuel injectors. Not sure if I can clean them. I may try pulling one and see first.

 

Ok raised the back, both spin good, no noticable drag. Just compared to my neighbors newer prius, and about the same. Id say mine spin quieter actually. But I did just do the brakes.

I hit the front and rear calipers with a laser temp and the front were slightly hotter than the back too, as I expected. Same with my neighbors.

I need to clean my rims better. Hands got filthy spinning em. LOL. I spent more time cleaning the wheel wells and chassis than rims :/

 

Ok after water pump and thermostat change and a quick hard flooring bad hard driving Im up to 38mpg on a quick 40 mile surface street and freeway run. And I drove like a race car driver. LOL

She runs and feels the same. I STILL think shes a little sluggish and hitting the power band in eco mode way too much. But its a better improvement in MPG anyways. I may do the fuel injectors if I dont get above 40.

Im gonna driver her around for a week and see how it goes.

12v holding 12.3 or higher overnight.

Rear wheels spin good. Front not as much. But the brakes are a week old. Im monitoring it might clean and relube. do not know what else I can do.

Tires still front 42 PSI rear 40 psi.

Maf good. No ECU codes. NO error codes. Some odd reading incomplete from torque. Any ideas?

 

OK, hoovering in the 35MPG territory, on highway it jumps to 40s, more city driving is goes as low as 33.

I will be doing fuel injectors after all, reading other reports that it helped others.

Question, should I replace my coil packs? They seems pretty costly and only seem like a replace it if it is bad item.