A couple of weeks ago I had a flat on the Interstate. They were doing construction, and I had to drive about 1/4 mile to get off the road. I replaced the flat with the donut...which was low in pressure. The car went into Limp mode. I got air in the donut and drove it "gently" home (10 miles). I took it straight in and got new tires--Firestone Affinity Touring. Now my gas mileage (on my regular driving route) is 10--15 miles lower! I checked the air pressure, and added up to 38 psi. The car seems to have more resistance, and I can't seem to get the engine to "rest" while driving...not like before. Does the limp mode need to be reset?
That is too bad about the flat tire. I hate it when that happens. What is the limp mode? Perhaps it needs to be reset. That is strange that the gas mileage is way down then before. I have had a total of four flat tires on my 2010 prius. (we'll say that I am getting good use out of the donut). I have never noticed a decrease in my gas mileage at all, except when it is cold, which is normal. Is there extra tread on the new tires?
>>Not that I know of...just NEW. The Limp Mode is when the car will not go over 35 mph if it senses something is wrong.
I do not see that Firestone Affinity Touring are Low Rolling Resistance tires, so they may never have as good as MPG as the OEM tires.
>> The Affinity Touring is supposed to be low rolling or high mileage...that's why I bought them. The tires I took off were WalMart Goodyear Vivas.
Last tire change on my '06 the tech ripped a tire so I only had 2 mounted, had to go back the next day, as the new tires were much larger then the old once I went over 32 the ice would stop, limped home, next day with the 2 new same sized tires the limp mode went away and had no reflection on future mileage, yer problem is rubber, and or an emergency brake rubbing
I bet your new tire has lots of resistance and sticks to the road which is causing the mileage drop. This happened with me too. With my original tires (Good year), I was getting 53mpg. At 55k, I got Hankook Optimo H727, mileage dropped to 48. Now I am at 80k, still get 48. Its definitely the tire. I am going to change my tires to LR atleast the fronts.
High mileage is not the same as LRR. I also don't see any indication the Affinity is a LRR tire. If not, lower MPG is to be expected.
Update...After 2 1/2 weeks, and increasing the tire pressure, the mileage is better. The sticker on the door recommends 35/32. The tires Max pressure is 44 psi. We increased the pressure to 42/4o, and started getting about 47 mpg--which is within 2 mpg of what we were getting before with the Goodyear Viva 2 tires. (Those Viva 2 tires were very cheaply made though. We had already replaced one for a belt separating, then the next one blew out and split up the side!)
The computers see one tire flat or low on air and kill the ice at 32mph, don't remember any icons on the dash, didn't look, was busy keeping on keeping on. Limp mode is exactly like stability control, the car is controlling itself, not allowing you to damage "it", actually, I vaguely remember the stability control light on while it was in limp mode, perfectly drive-able below 32mph.
