Question about the cruise control

[Red Baron]

When I set the cruise control, the speed varies plus/minus 2km/h from the set speed (so it's a 4km/h variation) all the time, up and down... Dealer says it's normal, some even vary by plus/minus 5km/h???

I need help on this 'cause I've had the car for 9 months now and I still get CRAPPY gas mileage, maybe this is one reason.

What do you all think, please.

 

[20ESGUY]

Yeah the cruise will vary a little even on a flat straight road. It's typical for cruise to do that in all cars. As far as the gas mileage don't know. It could be your altitude or cruising speed. anything at or above 80MPH will eat the tank, too many rpms for long distance crusing.

 

[Red Baron]

Yeah the cruise will vary a little even on a flat straight road. It's typical for cruise to do that in all cars. As far as the gas mileage don't know. It could be your altitude or cruising speed. anything at or above 80MPH will eat the tank, too many rpms for long distance crusing.

Thanks 20ESGUY.

I have no idea about the altitude, and it's almost flat. I've tried cruising at 120km/h (74.5mph) for about a month and then 110km/h (68.4mph) and noticed a small gas mileage diff.. Car now has close to 23000k (14.3k miles)

Reason why I didn't think this is normal (cruise problem) is because my previous cars equiped with CC were very stable. Maybe it's because the speedometer in Mazda products are very accurate.

Any other ideas?

 

[mazdadan]

Every Mazda I have ever owned with cruise control has kept the speed fairly stable. However, usually it will vary 1-2MPH depending on the road slope, etc.

 

[Sir Nuke]

It could be your altitude or cruising speed. anything at or above 80MPH will eat the tank, too many rpms for long distance crusing.

ACTUALLY .... this is not always true.....as this last summer on vacation I drove my wifes P-5.....on the highway we ran 85 for hours on end.....with the car totally loaded in the back up to the top of the rear seat....and had four people in the car....my gas mileage was between 29 and 30.5 MPG which is better than a lot of people get at a steady 60 mph.....so its pretty dependant on the individual car I think.

MY cruise control "hunts" too, I hate that.....some of my cars have done it..some havn't.....it the main reason I don't use it much.