Hey, a newbie WS owner here. Bought mine at auction and been steady working on it since... What I want to know is what kind of fuel economy all are getting. I have 97 3.8 with 120K, get about 20 MPG (up from bout 16 when first got it). Have done all routine type stuff( plug, wire, pcv, fuel, air). Notice what I would call a slight miss at idle. Keep getting P0304 #4 cyl misfire engine code. Took intake plenum off and cleaned all 6 EGR ports so I know that not problem. Thank you all. :screwy:

Hey, a newbie WS owner here. Bought mine at auction and been steady working on it since... What I want to know is what kind of fuel economy all are getting. I have 97 3.8 with 120K, get about 20 MPG (up from bout 16 when first got it). Have done all routine type stuff( plug, wire, pcv, fuel, air). Notice what I would call a slight miss at idle. Keep getting P0304 #4 cyl misfire engine code. Took intake plenum off and cleaned all 6 EGR ports so I know that not problem. Thank you all. :screwy:


20 mpg sounds about right, I get anywhere between 18-22. As for the slight miss at idle, I just cleaned off the MAF and it seemed to smooth it out.

I also have a 97 w/star 3.8, I get 26 mpg (Canadian Gallon)on long highway trip , lower in the city and of course much lower city driving in winter. As for your slight misfire and code ,many things to try out there as you will see checking all the forum. I would suggest a good dose of injector cleaner,,, could have slight vacuum leak somewhere, perhaps lower intake gasket which can sometimes be hard to find. sometimes too small to detect. ,,, good luck, When you find it , please post it .

I get about 22 in city driving, it runs smooth, sometimes I think it's quit!(Edit...knock on wood!)

For your misfire you might want to also change that plug and one by one disconnect one plug wire at a time and check and write down the resistance of each.
I bought a new set for my Taurus a year ago and one wire was dead out of the box.
Also check #4's injector plug connector for corrosion, looseness ect.
At idle you can also put a stethescope on #4 injector and compare the clicking to the others.
I remember reading a post awhile ago about a misfire code that was caused by a loose crankshaft position sensor and ring. Could be possible.
Hope something helps!
Randy

If you are getting the P0304, and you know that you have good plugs, (make sure that they are Double platinum), then it could be the fuel injector needing cleaning.

Run 2 treatments of a quality fuel system cleaner through (you should run a bottle through about 3-4 times a year).

I would recommend either Redline Complete Fuel System Cleaner, or Chevron Techron.
I have also been using the Redline in a "maintenance" dose.

IF that does not clear the code issue up, then you may have to remove the fuel injector and spray some cleaner up into the cup that is over the spray end of the injector. That is what I ended up having to do the clear up a misfire on one cylinder.
I could see the crud built up in there.
While I was in there....I cleaned all 6 injectors.

I had to do this, in spite of repeated fuel sytem cleaner treatments. I am told that this is normal for an injector in any engine with a lot of miles.

You will want to clean around the injector mounting on the surface of the lower intake manifold the best you can, and be careful to avoid having crud fall down into the lower manifold when you remove the injectors.

I get about 15mpg going 6 miles one way to work. I figure this is about the best I can get on this van. I have done all the regular stuff (filters, plugs, ECM reprogram). Highway mpg is about 22.

I am going to also say, the mileage in the cold weather is not worth worrying about....
I am saying this because I get worked up over my winter mpg....and have to tell this to myself....

It is VERY important to understand that different regions have different gasoline. In my area, we use one of the special "reformulated"....also called "oxygenated" gasolines. This type of gasoline will give you less miles per gallon.
If that is not enough......the formulation of the "reformulated" gasoline varys from area to area....and.....in many areas, including Southeast Wisconsin, there is a "summer formulation" and a "winter formulation". The formulations that we use in my area are ONLY used in Southeast Wisconsin and Northern Illinois.

To put it in a sentence..... Fuel economy....within, say 10% will vary on the SAME car with different gasolines....which will depend on what area you are in.