Poor Gas Mileage Improvement

[StCassel]

Since January '07, I had noticed a big drop-off in the MPG, on my 300C.
After 30K mile service, w/ new plugs, there was no difference. In July,
I went to my favorite vacation spot (same routes, used cruise-control,
used A/C, tires @ 30 lbs.) and got only 23.5 MPG. Previous trips I got
a MPH of 28-32 for an eight hour, mostly interstate trip. I have had
to struggle to get 13.4 around town, when I used to get 15-19 MPH.

Took it to my dealer and there was a TSB bulletin. TSB 1803104REV.A . The NGC Controller was reprogrammed. There has been some improvement in the MPH of my 300C. I have gotten 15.5 MPG around town. 24.0 MPG for an hour trip on interstate. That is an improvement over the 23.5 MPG for an eight hour trip in July. So perhaps the MPG of my C will be as it was last year.

StCassel

[GoofyTimL]

That still doesn't explain why it changed so much in January... it would imply something in the NGC controller needed fixed? What is the NGC anyway... never heard of that acronym.

I've never achieved anthing near 28 mph with either of two 5.7L 300Cs, although I have/do get near 25 mpg regularly on long highway trips.

[joey]

MPG is a squirrelly number. There are too many variables that can change the number. I once had the same thing happen to me after an oil change. 24mpg on the freeway before the oil change, then 20mpg after the oil change. I was certain the dealer had put the wrong oil in the car. Then a week later all of sudden I am once again getting 24mpg.

I have also seen unbelievable high mpg averages posted in some LXforums surveys.

Since day one, my average is consistently 15mpg. About 24mpg on the freeway, and about 12mpg around town.

What is strange is the TSB the dealer applied was issued November 2004.
Seems strange it would show up this late. But if it fixed the problem, that is all that counts.

[StCassel]

Originally Posted by GoofyTimL

That still doesn't explain why it changed so much in January... it would imply something in the NGC controller needed fixed? What is the NGC anyway... never heard of that acronym.

I've never achieved anthing near 28 mph with either of two 5.7L 300Cs, although I have/do get near 25 mpg regularly on long highway trips.

I have an early '05 300C (October '04). At the time, the MPG window sticker said that 25 MPG was the "estimated" highway mileage. I usually get 2-3 more MPG than what the MPG sticker states. That is an easy 27-28 MPG. In 2005 and 2006, I rolled into my favorite vacation desination with MPGs of 28 and 32. With 32 MPG, I said, "Hey, Al Gore... eat me!!!!"

I do not know what NGC Controller is either. MPG restoration is always good.

StCassel

[StCassel]

What is strange is the TSB the dealer applied was issued November 2004.
Seems strange it would show up this late. But if it fixed the problem, that is all that counts.[/quote]

Since I got my '05 300C in October '04, that may explain the '04 vintage TSB.

StCassel

[KRAZYCLC]

IF YOU THINK THAT POOR MILEAGE THEN READ THESE MPG'S.
IN NEW YORK CITY I GET LESS THAN 10MPG, THE HIGHWAY IS USUALLY 17 MPG.
TWO DIFFERENT DEALERS NO TROUBLE FOUND.
"THATS WHAT THE CAR REALLY GETS IN NEW YORK."
SAID A MANAGER FROM THE SERVICE DEPARTMENT.
THEY NEED TO CHANGE THE LAWS GOVERNING THE MPG.
NOT EVERY CITY HAS THE SAME POPULATION OR TRAFFIC PATTERNS. CHRYSLER AND ALL CAR COMPANIES MUST BE MADE TO TELL THE TRUTH; NOT JUST PUT AVERAGE MPGS.
NEVER BUYING A CHRYSLER AGAIN IN NEW YORK CITY. POOR SRVICE DEPARMENT, LIES, CAR RETURNED IN WORSE SHAPE THAN WHEN BROUGHT IN. 3 TIMES THEY GAVE ME THE CAR BACK WHEN IT WASENT FIXED, EVENTHOUGH THEY SAID THEY FIXED IT.THEY EVEN FRIED THE COMPUTER AND NEVER TOLD ME.
"IF THERE IS NO DTC THEN THEY CANT CHARGE CHRYSLER FOR THEIR TIME.SO THEY WONT SPEND THE TIME TO TRACK DOWN THE TROUBLE." THATS WHAT I WAS TOLD BY MECHANIC AT THE DEALERSHIP IN N.Y.C.

[greedyk]

Originally Posted by GoofyTimL

That still doesn't explain why it changed so much in January... it would imply something in the NGC controller needed fixed? What is the NGC anyway... never heard of that acronym.

I've never achieved anthing near 28 mph with either of two 5.7L 300Cs, although I have/do get near 25 mpg regularly on long highway trips.

NGC is "Next Generation Controller"
Gary

Edit:
Tim, just realized question was 5 months old!

[chuckkent]

I get 20-22 around town and 28 on trips to the lake and back. By carefully feathering the gas I can get as high as 31 between 55 and 50 mph for distances of 10-15 miles. My guess is that for some reason the MDS is not fully operational. I keep about 32-33 psi in the tires and make sure the engine has 5W-20 in it. I drive like an old lady....but am thrilled I get with in 5 miles/per gallon of the little sh1t box cars.......