[cmyk]

I know there are a lot of "bad gas mileage" threads, so sorry if this has been addressed as I'm sure I wasn't able to read through all of them.

I had a thread going a couple weeks ago about a sudden limp mode/half engine light followed by reduced gas mileage. Took the car in and had both Vanos solenoids replaced under warranty. This fixed the problem for about a week, but it has now returned. I was previously getting around 350-360 miles per tank of gas, and I'm now getting less than 250. So, something is not right.

I'm also smelling unburned fuel when I let the car sit for a minute at idle in the driveway.

I'd like to avoid another trip to the dealer as it's sort of an ordeal every time, especially if the problem they "fixed" just comes back again in a week. If there are things I could check out myself to at least narrow down the problem I would rather do the work myself, or at least get a solid diagnosis done on my own to be sure the problem(s) is/are being properly addressed.

At first I thought the usual coils/injectors/plugs, but I'm not pulling any codes and haven't experienced any misfires, other than a couple of isolated incidents over the past month or two where the car will "balk" very slightly at WOT. I attributed these to driver error, but maybe there's something else to it.

Can anyone offer any insight or direction I could take to narrow this down?

not quite 42k miles on the odo, Cobb stage 1 Aggressive, 93 octane. Other mods in my sig.

[qba335i]

You are within the range for gas consumption. My average is a little less then 250 miles per tank. I only have power kit and exhaust on my n55. This is a 3.0 motors with turbo... You can't expect Prius Like consumption.

[oshusttoley]

its no 4 cylinder

[cmyk]

Originally Posted by qba335i

This is a 3.0 motors with turbo... You can't expect Prius Like consumption.

I'm not.

My concern is not that the mileage is "bad." My concern is that, within a span of 2 weeks, the gas mileage has dropped nearly in half. You're saying that this wouldn't concern you?

ETA: Are you also saying that this, coupled with suddenly smelling strong unburned fuel at idle (that wasn't there previously), is also normal?

[wobbles1]

Originally Posted by cmyk

I'm not.

My concern is not that the mileage is "bad." My concern is that, within a span of 2 weeks, the gas mileage has dropped nearly in half. You're saying that this wouldn't concern you?

ETA: Are you also saying that this, coupled with suddenly smelling strong unburned fuel at idle (that wasn't there previously), is also normal?

If you were actually smelling unburned fuel at idle your o2 sensors would be throwing mixture codes like nobodys buisness. The problem is in your nose.

[gatoman39]

You moded the car, so since the car is probably out of warranty, where have you been getting it serviced? Have you had a COBB tuner look at it?

[cmyk]

Originally Posted by wobbles1

If you were actually smelling unburned fuel at idle your o2 sensors would be throwing mixture codes like nobodys buisness. The problem is in your nose.

That may well be the case, but this was brought up at my dealer visit a couple weeks ago when the Vanos solenoids were replaced, and my SA commented on it as well.

[cmyk]

Originally Posted by gatoman39

You moded the car, so since the car is probably out of warranty, where have you been getting it serviced? Have you had a COBB tuner look at it?

Not out of warranty. The dealer has been doing the servicing. I would be happy to do any non-warranty service myself, but so far it hasn't been an issue. Dealer knows I have a tune, and would be the first to tell me if the tune caused the issue. The issue is present with the tune installed or uninstalled.

Having Cobb look at it isn't a bad idea, though. Thanks for the suggestion -- not sure why I didn't think of that.

[Sam335ix]

I had ppk it was 18.2 mpg... now with JB4 its 17.2 mpg. It is what it is.

[wobbles1]

Originally Posted by cmyk

That may well be the case, but this was brought up at my dealer visit a couple weeks ago when the Vanos solenoids were replaced, and my SA commented on it as well.

say whateva you want if it was running rich you would have numerous faults.
If the o2 sensors see a rich mixture . you get a cel. You couldnt even smell gas before they would throw a fault.
my guess is you got a load of bad gas with either water or to much ethanol in it.

[cmyk]

Originally Posted by Sam335ix

I had ppk it was 18.2 mpg... now with JB4 its 17.2 mpg. It is what it is.

I understand that. I think what people are misunderstanding is that this is a NEW problem that came on suddenly. It shouldn't have anything to do with the tune I have on the car; as I said, the issue is present whether the tune is installed or not. I've had Cobb on the car for several months, same map, same version, same octane gas. The car was running beautifully 3 weeks ago. Then I got the Vanos code, had the solenoids replaced, and now this. I'm not upset about getting ~15mpg; honestly, I think that's pretty decent mileage all things considered. The thing that is confusing me is that this doesn't appear to be normal for the car, given that this literally started overnight, and it's such a drastic change.

I'm getting a lot of sarcastic comments, which is fine. Say whatever you want, and call me a stupid girl if it makes you feel better, but if you started noticing abnormal issues in your car that popped up overnight, wouldn't you be at least curious to find out what the potential problem was?

[Bronze]

Check your hoses, clamps, and check valves. You might have a vacuum leak and might be running rich, but not rich enough to set a code if the HEGOs don't detect something wrong.

[cmyk]

Originally Posted by Bronze

Check your hoses, clamps, and check valves. You might have a vacuum leak and might be running rich, but not rich enough to set a code if the HEGOs don't detect something wrong.

Thanks

[wobbles1]

Originally Posted by cmyk

I understand that. I think what people are misunderstanding is that this is a NEW problem that came on suddenly. It shouldn't have anything to do with the tune I have on the car; as I said, the issue is present whether the tune is installed or not. I've had Cobb on the car for several months, same map, same version, same octane gas. The car was running beautifully 3 weeks ago. Then I got the Vanos code, had the solenoids replaced, and now this. I'm not upset about getting ~15mpg; honestly, I think that's pretty decent mileage all things considered. The thing that is confusing me is that this doesn't appear to be normal for the car, given that this literally started overnight, and it's such a drastic change.

I'm getting a lot of sarcastic comments, which is fine. Say whatever you want, and call me a stupid girl if it makes you feel better, but if you started noticing abnormal issues in your car that popped up overnight, wouldn't you be at least curious to find out what the potential problem was?

obviuosly your vanos was not working correctly before you got the new vanos solenoid installed . your cars valve overlap has changed. now it is (working properly). Hense the lower mpg.

[Game]

Is it possible you got a bad batch of gas?

[cmyk]

Originally Posted by Game

Is it possible you got a bad batch of gas?

I thought that, and it may be due to the gas station I use regularly. But this has been going on for the past 2-3 tanks of gas, so unlikely.

[wobbles1]

[QUOTE=The car was running beautifully 3 weeks ago. Then I got the Vanos code, had the solenoids replaced, and now this..[/QUOTE]
You answered you own question. as stated before your vanos solenoids were not working properly before you had them changed. This effects valve timing.
They were not working properly before. Now they are. That is why you your fuel consumption has changed. IMO.

[iBoost]

you got 350 miles out of 1 tank? that's insane. ive always had about 260 miles out of one at the most... i think you might of had a problem before but i think now youre having the average consumption imo.

[cmyk]

Originally Posted by iBoost

you got 350 miles out of 1 tank? that's insane. ive always had about 260 miles out of one at the most... i think you might of had a problem before but i think now youre having the average consumption imo.

Well, that seems to be the consensus I guess. It just seemed strange to me.

I was averaging 23-ish mpg (combo of city/hwy driving). The Vanos codes popped up, gas mileage went down to ~10, Vanos solenoids replaced, gas mileage back up to 23 for a week or two, now back down to 12-15.

So it is what it is, I guess.

[Sam335ix]

Originally Posted by cmyk

I understand that. I think what people are misunderstanding is that this is a NEW problem that came on suddenly. It shouldn't have anything to do with the tune I have on the car; as I said, the issue is present whether the tune is installed or not. I've had Cobb on the car for several months, same map, same version, same octane gas. The car was running beautifully 3 weeks ago. Then I got the Vanos code, had the solenoids replaced, and now this. I'm not upset about getting ~15mpg; honestly, I think that's pretty decent mileage all things considered. The thing that is confusing me is that this doesn't appear to be normal for the car, given that this literally started overnight, and it's such a drastic change.

I'm getting a lot of sarcastic comments, which is fine. Say whatever you want, and call me a stupid girl if it makes you feel better, but if you started noticing abnormal issues in your car that popped up overnight, wouldn't you be at least curious to find out what the potential problem was?

I wasnt being sarcastic, calme down. You need to have it looked at by the dealer and let them know about the MPG differences after and before any work was done and see what they come up wiht. GL.

[cmyk]

Originally Posted by Sam335ix

I wasnt being sarcastic, calme down.

That statement wasn't directed at you. Your post just happened to be the one I was replying to when I said it.

[ss134]

I would eat my grandma out to get 250 miles from a tank.