My Gas Mileage sucks

[83countrysquire]

I have done a full tune up on my car. I mean New plug wires cap rotor tps iac egr, fuel pump and I did the exhuast too dual with headers and cats. According to my tripminder ( I think it might be just un accurate cause it seems screwy but I havent gone thru a full tank yet to fill up and see but anyways) i am getting 9.8. Thats not even flooring it. I do know that the ford dealer ship disconnected the thing that adjust my timing automaticly because it was making my car stall i believe it was the tif. (thing on bottom of base of distributor looks like a key kinda) could that be it??

[70torino429]

if your talking about the tfi module on the side of the distributor, i dont know if it will even run like that, if it did run with that disconnected, it would sure run like crap.

[fairplay]

Welcome to the terrible gas mileage club. Seriously, though, the TFI module either works or doesn't in most cases of my experience, and I've had a lot with those modules. Ever do your wheel bearings?

[83countrysquire]

Not yet. The thing is I wasnt getting bad gas mileage till now before my exhaust rotted off I was gettin like 17 around town.

[fairplay]

Exhaust can be somewhat funny that way. The back pressure it creates on your engine can be beneficial, but I don't know enough to comment on it. (leaves door ajar for smarter people....)

[Lincolnmania]

have you done a vacuum reading?
have you checked for stored trouble codes?
check your tire pressure
good one fairplay.......make sure the wheel bearings are decent, also make sure that the calipers/wheel cylinders/e-brake cables are not sticking......drag= poor fuel economy

[91waggin]

you're sure the speedo is getting accurate readings? you might not actually be getting 9.8

[83countrysquire]

I havent checked my speedo or the vaccum readings will do tho. How do I check error codes. Also I think your right on wheel bearings cause I just remebered but forgot to fix it that when I had my front end jacked up I spun my front tires and it sounds as if my brakes are scraping rotors when I am not on the brake! So I believe you guys might be onto something and with the back pressure I think you might be on to another thing I am just running dumps right now cause I just mount mufflers and tails havent had the time to do tail pipes. But when I replace my rear and drop my fuel tank again I will be putting back on my tail pipes. Thanx for the help I ll have to fix these issue and give you some feed back.

[mrltd]

if the timing isn't doing anything it's not gonna get any decent milage either.

[packman]

I guess every engine is different because the 2.5" duals I put on my lopo neither helped nor hurt fuel mileage. Wheel bearings and rear drums should be checked to see if nothing is dragging. Your tripminder is probably a little screwy.



Packman

[gadget73]

Calculate your gas mileage the old fashioned way, miles divided by gallons. Let us know what you're really getting instead of just what the tripminder thinks. It could be screwy.

[P72Ford]

+1 on what Thain said. You need to make sure the tripminder is actually fairly accurate.

If it is correct, I can't see the exhaust causing that significant of a drop in fuel economy. 2.5" exhaust is too large for a stock engine, but the adverse effects shouldn't be that noticeable.

[83countrysquire]

my exhuast is 2.25

[P72Ford]

That isn't a problem.

[351m]

If the dealership disconnected the TFI module it wouldn't be running, if they pulled the spout connector and left it out though... You would be running at a constant 10 deg. timing and probably get NO power, and NO fuel milage.

As for the exhaust, 2.25" is fine, dumps or tails make no differance. The spout connector is on a little socket on the harness to the TFI right near its plug.