Terrible MPG on 2004 Rendezvous 15 MPG!!

[Yaser]

Hello Forum Member,

I have a 2004 Buick Rendezvous AWD with 223000 km. The mileage on the car is horrible. I have tested it on highway and the full tank (62 L) is completely gone after around 390 KM. This means it uses about 16L/100km or around 15 or less MPG. I am wondering if anyone else has the same experience and if this is usual in this cars?

I have to mention that I bought the car as a used car on Feb 2012 and it has been like this since that time.

Any feedback, advice, thought is highly appreciated.

Kind Regards,

 

[jimmyh]

There's a lot of things that can cause it. Main culprit would be the tires. If they are worn, if the alignment is off, they could be a lousy tire that has a lot of rolling resistance. Or there could be an engine or drivetrain problem.

 

[Buick Customer Service]

Hello Yaser,

Thank you for bringing this to our attention! For further assistance, you may contact our GM of Canada at 800-263-3777. We hope to resolve this issue quickly for you!

Jessica
Buick Customer Care

 

[Yaser]

Thanks for the two replies. I am wondering if anyone can tell me what the MPG is in their Rendezvous. I want to know what I should expect. The tires are good and not worn. The alignment is checked with no issues. There is no engine light so I am not sure if there is an issue with the engine. If I want to have it checked what I should check?

 

[hennit_seebo]

I have an 03 vous FWD. and I get around 24-25 on hwy And 18 or so in town depending on how much of a hurry I'm in.

If I were you I would make sure every maintenance item is up to date. A combination of things can decrease mpg.
Check:
Plugs/wires
Fuel filter
Air filter
Tires/alignment/ pressure
Sticky egr valve can cause poor mpg as well.
Carbon build up on idle air control valve

Any gas smell when car is off or running? If so possibly a leaky line or leak on top of the tank.

 

[Yaser]

Thanks for your reply and from yours I think there is hope to get a better mileage someday (maybe).

From the items you mentioned all is good except I haven't checked the plugs/wires and the valve. Also there is no smell. I have to find a solution because these days I am having so many road trips (work trips) and I am renting cars which is cheaper than taking my own car.

 

[typhoonk]

check out -> http://www.fuelly.com/car/buick/rendezvous/2004

you can use that site (even mobile site) to track your own mpg.

and here's the .gov -> http://www.fueleconomy.gov/feg/bymodel/2004_Buick_Rendezvous.shtml

old post about the same thing -> http://buickforums.com/forums/showthread.php?t=335


seems like the best average fuel economy is around 19mpg.

don't buy the RDZ if you want great gas mileage. Not that most vans would be any better.

Would be interested in knowing if there is another GM engine that would swap in and use less fuel? maybe a 3.6 or 3.8L?

 

[Yaser]

Thanks for the info.

 

[hennit_seebo]

Just thought I would mention even though i already have 🙂 I just got 28 MPG on a 2 hour trip this afternoon. driving 55 the whole way with a few towns in between. 🙂 So far i'm impressed with this SUV

 

[Yaser]

This is a miracle. I didn't change anything! I didn't do anything! I didn't take it to any mechanic or auto shop. But this weekend I had to go for a quick job related trip out of city and I got 28 MPG driving 100 KM / Hour. Well, this is great. 🙂 I am going to do another test trip next week and will post here how it goes. Thanks everybody

 

[Yaser]

This is a miracle. I didn't change anything! I didn't do anything! I didn't take it to any mechanic or auto shop. But this weekend I had to go for a quick job related trip out of city and I got 28 MPG driving 100 KM / Hour. Well, this is great. 🙂 I am going to do another test trip next week and will post here how it goes. Thanks everybody

Sorry NOT 28. The correct MPG is 23 or 24. Math issue 😉

 

[2004buick]

My 04 gets around 22 to 24 highway and 15 to 17 city driving I have 187K on mine

 

[txbarney]

I suspect the 2004 has a 3800 V6 and a bad cam sensor can lower gas mileage and affect performance. It is seldom the sensor but is most likely the trigger magnet has come out of the end of the cam.

Another less likely sensor failure is the knock sensor, if it goes high, the ECM will retard the timing and gas mileage will be affected.