[RmTrice07]

EDIT: Sorry, title is RPM not RMP

Hey all! This is my first post on this forum. I am a proud owner of a 2009 Ford Focus SES Coupe, and I have a question for you all.

My sister and I essentially have the same car, only her's is a 2009 SE Sedan. I drove her's on the interstate today and noticed a few shocking differences between her car and mine.

Her car cruises 70mph at about 2500rpm getting an indicated 38-39mph. 75mph will get about 2900-3000rpm at 35mpg.

My car cruises 70mph at 3000rpm getting about 32mph and 75mph at about 3400rpm getting roughly 28mpg.

Her car has almost 40,000 miles on it wheras my car has about 33,900. My overdrive is turned on like it should be for every car. Her car also seems MUCH quieter and more solid vs. mine (although I attribute that to her new tires. Mine are 2 years old and came with the car brand new)

Naturally, this is driving me insane. I drive on the interstates about 80% of the time since I have a 27 mile commute to work. Fuel efficiency is of the utmost importance to me, but im also concerned about undo stress the engine may be getting from this. To get the 3000-3500rpm on my sister's car, I'd have to hit nearly 85mph.

What is causing this, and what can I do about it? I'm feeling rather unsettled about it. Thanks.

 

[sleepyboy]

Ok the coupe has a different final drive ratio on the transmission than the sedan. Ford did this starting in 09' I believe. This is why you are seeing a slight difference in indicated RPM vs speed. This is also why hers gets slightly better mileage. Now her driving style could make up for the added efficiency also. Girls tend to drive a little less aggressive. So with those two factors it totally makes sense in what your describing.



Oh and welcome to the forum [welcome][ffrocks]

 

[Elizabeth]

The quick thought is your car is never going into overdrive at all.
With the identical transmission, and IF she has not gotten MUCH bigger tires or something..
So i would say your vehicle is locked out of top gear, or out of overdrive somehow.
I do not know if you guys have a five speed, or four speed automatic tranny with overdrive.
But iwould bet your's is not working right.
(One other small possibility is one of you have a different tranny altogether?)
Coupe and sedan do have different final drive ratios? that is it.
Sportyness vs MPG.

 

[RmTrice07]

Sleepyboy: Well, I reset the MPG indicator once I got onto the interstate. She has admitted to being a led foot, though, and her overall MPG was 23mpg before I reset it. Mine usually stays at 27-28mpg. Thanks!

Elizabeth: Thanks for the input. I tend to agree with your theory more, however my car has driven like this since I bought it brand new with just 45 miles on it. So I probably do have a different final drive ratio than my sister's car. I just wanted to make sure there wasn't something wrong with my transmission or something. Two cars with identical engines of the same year, make, and model cruising 500-600rpm apart from each other seemed weird.

 

[whynotthinkwhynot]

Do you both have ATs MTs or what? The final drive ratio is different between MT and AT.

If you both have ATs, then Sleepyboy's explanation is one that might have some value. What you need to do is get the axle code off the sticker on the door, or (this might be easier) get your VIN, and enter it into our VIN decoder in Ford Focus Technical Chat Stickied threads or stuck at the top of this forum's thread list. That will tell you what your differential ratio is. You can also enter your sister's VIN to see what her's is also.

On the chance that you both have the same differential ratio, I'd say that your torque converter is not locking up as it should. The electronic lock up torque converter was invented by GM back in the 80's, but now everyone uses it to some extent. The hydraulic lock ups never worked reliably. If you pay really close attention, you might feel it. The best way to feel it is to force the transmission to stay out of 4th or OD. The converter will still lock up in 3rd, but not 2nd. After going a steady speed in 3rd for a short distance you should feel a slight push- it will be easier to feel at lower speeds- and that will correspond to a slight drop in rpm on your tach. Push down the accelerator slightly, and the rpm will go up slightly before you slowly accelerate. It will lock up again once you reach a steady speed or sometimes will lock up during very light acceleration.

If you're not feeling any of that, you might want to see if there is a fuse associated with the torque converter in the fuse descriptions in your owner's manual. If that isn't blown, then I'd first try a PCM reset before taking it to the dealer. Remove the negative battery terminal for 10 mins, then replace the terminal, and start the engine without touching the accelerator. After the engine is warmed up, you'll notice a slightly higher idle that might fluctuate. Allow the engine to idle for 6-7 mins while the PCM performs a 5 minute timed Air/fuel test. When it's done, the idle will settle down to it's normal level. Now see if you can feel the torque converter lock up, or if your rpms drop slightly at highway speeds. If not, take it in for service.

Of course if the differential ratio is different, then there's nothing you can do about that except trade it in for a car with 4 drs.