Can a clogged fuel filter cause bad gas mileage?

[Patman]

quote:

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Originally posted by ZR2RANDO:
Usually a clogged filter (any kind-oil/fuel/air..) shows up only at high flow rates, low flow rates still flow enough. If the fuel filter was really clogged you would notice lack of response at high rpms, same with catalytic converter, any clogging would be noticed at higher rpms (would give lower mpg due to exhaust gas resistance).
Winter driving always gives me slightly less mpg and slightly better driveability---cold air expands more in the cylinders.
Some vehicles burn some brands of fuel better than other brands too.
good luck

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I haven't tried changing brands of fuel yet, but then again this car has always run the same fuel and gotten better mileage in the past.

Based on the above post my problem can't be catalytic or a clogged filter, because the car runs great and still feels strong (as 106hp can) at upper rpms. No power loss.

And as I've said before, the plugs I pulled out looked good, not fuel soaked at all. It's almost as if my wife is driving around in 3rd gear (although I know she is not)

 

[TheLoneRanger]

Patman, does the MIL or CEL come on when the key is turned on, and then go off when the car is started? The reason I ask, if the MIL/CEL bulb is blown, there could be a code triggered and it not be apparent. If the light comes on with the switch, then the bulb tests good.

The Civic could have a bad sensor (temperature sensor comes to mind) that keeps the ECU in warm-up mode/open loop all the time. This would make the engine run rich and get very poor mileage.

A bad sensor will always keep the MIL light on though, so if the bulb is OK, disregard all this.....

 

[Patman]

That's a good point, I never thought to check for that! My wife drives the car most of the time so I never thought to check that, but this weekend I'll make a point to drive it and see if that light comes on during startup. Thanks!