2005 pontiac montana sv6 with 3.5 engine hard on fuel

[chevy2]

i have a pontiac montana sv6 extended van with a 3.5 engine.it,s been really hard on fuel and i would like some opinions on what it could be.heres the history of my van,i,ve had it since 2007 ,has 263,000 km on it,replaced both o2,s done a complete tune up,couldn,t change fuel filter doesn,t have one on the underside of vehicle.
my van has giving me great service until now and haven,t really done nothing more than regular maintinace.the engine check light has never come on,i only changed the o2,s because of my problem and mileage.i have my own scanner and all the data looks normal.
i pulled a couple of plugs and the engine seems to be running lean.now i have a rotted egr tube and a slight ex leak coming from the egr area.but the check engine light is not on.you would think that the check engine light would be on.would a leaky egr tube cause my hard on fuel issue. my van starts and runs great other than my issue i,m having.any suggestions would be appreciated.

 

[melsg5]

What miles per gallon are you getting?

 

[chevy2]

i,m getting roughly 398 miles out of a full tank.i use to get at least 600 or more.it,s a little harder on fuel now, because of winter, and since the summer of 2013 it,s been getting pretty crappy fuel mileage.

 

[melsg5]

I guess you are saying you got 24 mpg and now are getting 16 mpg? The vehicle when new was rated at 16 City 23 Highway with a combined of 18.You dont seem to be that far off the EPA rating. Have your driving patterns changed? Have you considered the mileage on the vehicle may have an effect? Are you tires properly inflated?

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[chevy2]

the milage on the vehicle may be a factor for high fuel usage,my tire pressures are spot on,check them regularly .driving patterns are pretty much the same.my tail pipe is pretty black with soot and this is a good indicater of running overly rich.i,m gonna get a new egr tube and try that.if the new egr tube works i will post my findings.

 

[melsg5]

pull the vacuum line off the fuel pressure regulator and look for gasoline, if you see it replace the FPR