Taurus (Ok, Sable) Falling MPG

I know this is a sable, but with the much larger Taurus forum and the virtually identical setup of the taurus and sable, I was hoping to get some ideas here.... :)

Have a 2001 Sable LS Premium, Duratec 3.0, 183,000mi.

Recently had a problem with rough morning idle and with an intermittent rough idle when stopped for lights and traffic.

Long story short, chased symptoms and occasional code and replaced EGR, IAC, DPFE, Fuel Filter, PCV, PCV Hoses, a few vacuum lines, upper and lower intake gaskets (orings), spark plugs (platinum), spark plug wires, air filter, and cleaned MAF and throttle body. Probably a few other things I'm forgetting.

Car runs perfect now, idles great, no rough idle at any time any more, even 15 degree mornings when it was at it's worst before.

However, I used to get about 28-29mpg almost every tank (commute 125 miles a day all highway). I'm down to about 23-24, last tank was actually only 21mpg.

Any ideas as to why my fuel mileage might be so much lower now? Is it just the 183,000 miles catching up with the old girl?

Thanks!!!

Any chance you're just driving it harder now that it's running so well?

Have you checked the air filter, cleaned the MAF, checked the coolant temperature sensor, tried using a bottle of fuel injector cleaner, or recently switched to an ethanol-based fuel?

-Rod

Have tried everything you listed with the exception of the coolant temp sensor. Been using 10% ethanol fuel in NJ for a long time now, years. The dash reads correct (cold in the morning, mid-guage once warmed up) but I've heard that's using a different sender completely. I also have been setting the cruise at 65 the last few tanks to make sure my driving habits have not been the issue. The 21mpg tank had more over-the-weekend local driving but I can't remember ever getting under 24 before, ever.

Might just be getting old.

well last tank was back up to 27 and change per gallon, haven't changed anything. Maybe the computer was readjusting itself after being powered down multiple times over the last 3 weeks (I remove battery cable when working on engine as a habit).

Thanks.

I have a simular question about MPG. I have a 1996 Taurus wagon with an ohv V6. The cars window sticker said the mileage should be about 20 mpg city and 29 mpg highway.
I just want on a 500 mile vacation and emptied an entire tank cruising at about 65 mph on the interstate and all I was able to get was 20 mpg.
The car purrs like a kitten and only has 68,000 miles on it and I checked all of the normal stuff (plugs, filters, etc) and there seems to be nothing wrong. I bought the car used and have put about 2000 miles on the car and consistantly get 20 mgp.
Any idea what I should check next?

Rod and others have always talked about the coolant temp sensor when someone has had unexectable fuel milage??
Could someone please tell me what the coolant Temp Sensor in my 02 24v 41K has to do with ones mph?? I have never had better than 18 mph around town and drive very easy.
New plugs & wires new air filter
New fuel filter
cleaned MAS
Fuel cleaner in tank
etc etc.
Thanks,
Rob Roy

The Coolant Temperature Sensor (CTS) is used by the PCM to modify the fuel mapping and timing. Based on what temp the CTS thinks the coolant is, the PCM will enrich or lean out the air/fuel ratio.

-Rod

Another thing that can cause bad milage that's often overlooked is having a hidden problem with the brakes...