Need Help QUICK! MPG dropped BAD and high RPM!

*edit* This an old thread.

I'm on a 5hr trip to Arcata and since we started the car is running at 2500-3200 rpm trying to maintain 70 mph. Gas mileage instantaneous is 29-32 mpg and average is 35mpg. The hybrid system appears to be working, the brakes are not hot . The front brakes are cold! No obstructions in the intake that I can't see. No warning lights. The only recent change to the car was a headlight swap last night but I did it the easy way and didn't take anything apart. Scangauge tells me my average speed is anywhee from 0 to 137 for this tank. I filled up this morning and just used half a tank to go 154 miles.

I'm driving so can't check this often so if Patrick or someone would be willing to call me it would be appreciated.

 

I really appreciate the help guys.

I don't normally freak out about mpg but this is a really odd situation. Normally at 70 mph I see an average of 45 mpg with this 17" wheel/tire combo. In this case I was experiencing as low as 29 mpg instant while trying to maintain 70mph. RPM was i'll the 3000s. It was crazy because the was no wind and I was on very flat highway. Even trying to accelerate from a stop briskly but not aggressively it would rev up to 4k trying to get up to 40 mph.


SOC was solid at 65-66%

Scangauge buf was 45-60

12v battery is an Optima and i've had the stereo off for a couple days so charge should be good.

I only changed the HID bulbs last night. The 55w HID kit was installed weeks ago and mpg was good until today.

Here is the variable. I swapped my 15s out to my 17s a few days ago. Mpg dropped from 51mpg avg. to about 46 mpg avg. on then same commute. I expected this as it always happens when I swap. This time the tires make a thumping sound at low speed like one is out of balance. I realize this is not good for mpg but for the last few days my mpg was normal for this combo. Until today that is.

Now after I posted this thread, we started up the the mountain (Trinity wilderness area from Weaverville to Arcata) and by the time we got to our destination I was at 42 mpg avg. So climbing up and down the Coastal Range at high speed netted me better mpg than flat freeway (35mpg vs. 42).

Could there be something going on with the tires all of a sudden? They are about 4 years old.

InThe mean time i'm going to reset the battery as per Patrick's suggestion.

Thanks again guys. I'm worried it is the transaxle.

 

Good call. We took 5 because 101 is closed. From Davis to Weaverville is were the worst of this was happening.

I checked the brakes pads, parking brake, air filter and induction, all engine plugs or connections, I wasn't in B mode, the car pulls slightly to the right but not bad enough to causes this. Oil level is perfect as well.

When accelerating is feels almost like a slipping clutch in that it revs up much higher than it normally does.

 

Lug nuts are tight and wheels appear snug against the hubs

While running the voltage reads 14v. And thanks for the reminder!

I tried with headlights off and on for long periods with no change.

The Tires and brakes were cool to the touch. The coolant pump was replaced in Dec as part off the recall. I can't warp stealth burn it is sometimes more difficult because these performance tires do not glide well. They never have.

 

NoDogs and the battery temp is good.

Tires are at 52/50. Both drums were slightly warm but just barely.

I tried the battery reset and around the block it seemed to be fine but once I hit the highway the problem was stilk evident. 65mph showed instantaneous of low 30 mpg. Grr

 

Changed it 3 weeks ago. It is still clean.

I 'mgoing to drive it home tomorrow and put the 15s back on to rule out the 17s and tires. I've never had this problem with them before though.