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I know its more then likely posted on here before but I have a 2004 6s 3.0L that is giving off a fuel odor when parked and at stops, and recently the mpg went down alot. The odor proplem has been there for awhile but is getting worse but the mpg just started. I had the car in my garage last night to find this leak, I'll tell you what I did.
1. pulled the rear seat to check the pump, no leak
2. checked the lines under the car , no leak
3. pulled the air box and checked the connection from the gas line to fuel rail while running no leak
4. checked the pressure regulator no leak externally or internallly
5. removed upper intake check injectors, no leak
I noticed a strong smell of fuel in the intake. The ports had some gas in them but maybe it was running rich due to haveing the MAF disconnected. I have no engine codes the only things I can think of is the evap canister ( was unable to find it) or a leaking injector( i have no way of testing that since it is a returnless system). Does anyone where Im losing this gas at?
 

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Last winter I had the same issue. I would remote start my 6 and after it ran for a few minutes I would get in and smell fuel. It wasn't extremely strong, but it was very evident. Turns out my spark plugs weren't torqued down tight enough, and I was getting some blowback...not good. I found this out when I blew 2 plugs out of the cylinders and stripped the threads. When they were helicoiled and reinstalled late last winter, I haven't had the same issue since.
 

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I have this issue too with my 2003. It only smells like gas when it has a full tank though. One time after I had just filled my tank, I let it sit over night and when i came back in the morning it had leaked about an 1/8 of a tank of gas on the ground. It has never done it sense, so I'm not sure if it was just pressure buildup from being cold outside and haveing a full tank, and gas just got pushed out the overflow or what happened.
 

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I have this issue too with my 2003. It only smells like gas when it has a full tank though. One time after I had just filled my tank, I let it sit over night and when i came back in the morning it had leaked about an 1/8 of a tank of gas on the ground. It has never done it sense, so I'm not sure if it was just pressure buildup from being cold outside and haveing a full tank, and gas just got pushed out the overflow or what happened.
If it's cold outside, the volume of the liquid would decrease. If there was an overflow, it would have had to happen on a really hot day. Temperature and Volume are proportional (increase temp, increase volume).

Anyway, I believe it is normal to have a slight fuel smell when starting the engine, as it goes full rich mixture and then adjusts as the engine warms up. (Someone correct me if I'm wrong?)
 

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I just solved this on my car. When running, the top of the engine would smell like gas, and the passenger compartment would also smell like gas - very annoying!

Solution: tighten the spark plugs! Apparently, they seem to work loose sometimes, and let some gas/air mixture past them. Also seems to burn up the coil packs too as a result. It was an unexpected solution for sure, but it was definitely it for me!
 
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