Fuel System Issues

[cfrierson11]

My car is basically my weekend driver. I get in it this weekend and as I'm driving, I feel like I can notice the fuel needle dropping faster than normal. I scroll over to my fuel mileage tracker on the SID and it is in the SINGLE DIGITS. The car seems to other wise be running fine. It idles well, still very responsive to the accelerator, and I have no CEL light to read any codes. Really don't know where to start. The piece around where the air flow sensor sits was deteriorating and was patched with a silicone like substance, but before that there was a CEL about the air/fuel mixture and hasn't been on since. So now I don't know what the problem is, or could be. Please Help.

[Digger]

When a car that should get more than 20 to the gallon gets less than 10, you should be able to smell the unburned gas. Putting your hand in front of the exhaust pipe and then sniffing the moisture on your hand isn't the most scientific method, but if a couple seconds in front of the pipe soaks your hand with unburned gas you know you have an emissions problem. If it doesn't, best start looking for a gas leak.

Weekend driver leaves a lot to the imagination as to how you drive on the weekends. If all your weekend trips are short and city slow a couple cans of seafoam in a full gas tank and a good cross country drive might be all your car needs. If you have some cross country freeway but mostly city slow, a power off reset for the engine computer might get the job done. If one or both of these doesn't put you back on track, you will need to plug in and look at the sensor readings to see what the ECM sees and go from there.

[cfrierson11]

Thanks for the insight. I'll definitely those options a shot. I haven't smelled any gas, nor have I seen any spots on the ground that would suggest I'm losing fuel. The type of driving I do with it is mainly commuting, highway/interstate driving. Not much slow, or stop & go traffic around me. I'm just thrown for a loop because it came from nowhere and has been running fine, and getting great highway mileage, until yesterday, but hasn't thrown a code. I'll mess with it during the week and see If I can smell gas in the exhaust first. Probably go ahead and put some seafoam in it also. Thanks again.

[yazdo]

I'm no expert here but maybe it's the fuel pump?

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[cfrierson11]

Not a bad suggestion. I’m certainly no expert myself, but I thought it might be running bad if it was anything with the fuel pump. But I guess it could be anything at this point. Lol. I’m going to do a little more trouble shooting, but I found a local mechanic who said he can hook up to it if I need him to.

[Digger]

If you're not leaking gas and you don't see a gas stain on the bottom of the car from the return fuel line you should be able to smell the gas coming out of the tail pipe, but gas does smell different coming out of the tail pipe than it does when it comes out of the pump and you might not know that smell. Before running off to the mechanic for a pricy diagnostic, check the fuel pressure regulator vacuum line for sign of moisture or the more familiar gas smell. Never had a regulator spring a leak this big in one day, doesn't mean that it can't happen.

[cfrierson11]

Ok. Thanks. I’ll give it a look. Where is that located? Easy to get to?

[cfrierson11]

Took it for a ride this afternoon after a quick "reboot" and adding seafoam to my fuel. I drove around for a good bit and got down on it pretty good to see how it would perform and to try to get the seafoam through the engine quickly; all to no avail. No improvement in the gas mileage.

[yazdo]

I had a MPG issue as well. Mine turned out to be that half the gasket in my throttle body had gone missing.

Another non-expert guess.

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[cfrierson11]

Oh, wow. Did you have any leaking issues? That's what throwing me off so bad is i'm not getting any codes, and i'm not, at least i'm not aware of, leaking any fuel. I can't smell gasoline, I don't see any spots after I park, and I don't see anything coming out of the car other than what comes off of the air conditioner.