: Fuel economy worsened and a shimmy



NuB
04-26-09, 03:01 PM
Hello,
I've only had my 2004 AWD N* V8 SRX for couple weeks. I bought it because I liked the comfort and ride and I enjoyed the power of the V8 compared to my other vehicles. So I did not buy this for fuel economy. However I was thrilled that it was more economical than my other cars/trucks. Now that thrill is gone.

I used to get 23 mpg on highway and 18 mpg in the city. Now the highway mileage has not changed much but in the city I get barely 16. I know it's only 2 mpg but something has changed and it's not my route to work or my driving habits. If anything I'm easier on it than when I was first trying it out.

I noticed a rotten egg smell once on the way to work but rather than think it's the cats on the SRX I thought maybe the vehicle before me caused the smell as we accelerated from the lights. I have not smelled it since either but wonder if cats were/are gone and ruined the 02 sensors. Truck has 60K miles.

I also know that my other vehicles had their fuel consumption worsen (actually double) yet I get no codes or anything. I attribute it to worn out sensors but don't know which ones and did not feel like spending $1500+ on all of them per vehicle. Now I may have to replace some here. So I figured I'd ask where to start based on other people's experiences. I don't want to go to the dealer just yet as not to get the courtesy ECM flash to take away the power. Plus with no codes, I doubt they'd really discover or fix anything.

I was watching the instant fuel consumption and I think it is now much worse on acceleration than it used to be, hence more mpg in the city with the stop and go traffic rather than worse mileage across the board. Are the engine or transmission ECMs ones that learn your driving habits and adjust shift points or fuel delivery accordingly? If so how do you reset it? (as I liked the vehicle the way it was when I got it)

I also noticed a bit of a shimmy in the driveline, I think, that was not there before. It appears at 60mph+ and it seems to get worse with speed. So I do not think it's the tires. Again, is there some most common cause of these that people know about? It is minor but bugs me because it wasn't there before, so I know something wore out a bit. And again I'm sure dealer may dismiss it as either normal or may not really find it (I'm kind of a very picky person compared to most).

Thank you for any insights.

edvanp
04-27-09, 07:09 AM
I was getting slightly worse numbers with my 05 V6 AWD (17/21). I recently ran Lucas Fuel Treatment in two consecutive fillups and drove to Chicago and back (230 miles each way). The mpg jumped up to 23.5 averaging approx. 70-75. It also seems to be running better now too. Maybe run a good fuel treatment and see if that helps. Lucas Fuel Treatment, Redline SI-1 and Techron all get pretty good reviews. Another thought, maybe switch where you get your fuel from, unless you don't get it from the same place. I know my cars seem to run better on BP, Shell or Mobil then the local discount station.

wait4me
04-27-09, 12:37 PM
If you have 60k miles, your cats should still be under warrenty. Go to the dealer and ask. I have seen SEVERAL bad cats in less than 60k on that year.

NuB
04-27-09, 09:33 PM
If you have 60k miles, your cats should still be under warrenty. Go to the dealer and ask. I have seen SEVERAL bad cats in less than 60k on that year.

You're probably right but as mentioned I'm dreading or avoiding the trip to dealer. Any good way to tell if the cats are bad?

NuB
04-27-09, 09:35 PM
I was getting slightly worse numbers with my 05 V6 AWD (17/21). I recently ran Lucas Fuel Treatment in two consecutive fillups and drove to Chicago and back (230 miles each way). The mpg jumped up to 23.5 averaging approx. 70-75. It also seems to be running better now too. Maybe run a good fuel treatment and see if that helps. Lucas Fuel Treatment, Redline SI-1 and Techron all get pretty good reviews. Another thought, maybe switch where you get your fuel from, unless you don't get it from the same place. I know my cars seem to run better on BP, Shell or Mobil then the local discount station.

Well I was almost worried that that's what did it. I put a can of injector cleaner through it. I always get gas at the same place. It happens to be Shell.

NuB
05-02-09, 11:57 AM
Any more ideas, opinions....?