I was just wondering what kind of gas mileage others are getting...

I have the feeling like I'm getting REALLY bad gas mileage, I typically get about 15 MPG on the freeway and probably somewhere around 10 MPG around town. Does this seem bad? I have a th700r4 tranny, and 3.08 rear end, turning about 2100 RPMs on the freeway.

What can help my gas mileage? I have new injectors, and a new Fuel Pressure Regulator. If anyone could tell anything by looking at data logs... you can view the most recent ones here. To me, it's running pretty well as far as logs go... any ideas?

Thanks.

 

Yes, considering that I used to get 18MPG on the highway with a TBI 305 backed by a 700R4 and a 3.08 gear in my '87 K5. Thats a fullsize 4X4 truck. The only thing I can figure is that it had 31" tall tires, so my effective gear ratio is lower than yours, but the truck is a brick in a wind tunnel. I'd think the vastly superior aerodynamics of a 3rd gen would more than make up for it.

 

Are you running higher flowing injectors on your stock chip? That will do it if so.

 

I am getting 17mpg with mixed highway/city with my 305TPI Formula Auto. I have a heavy foot and accelerate to the speed limit very fast.

 

My car is parked for winter but in the summer time i was getting close to 28 mpg (US gallons) on the highway and that was at various engine speeds.

I used to get much lower mileage untill i started getting into the PROM and playing with the Highway Mode. Once you active it, you can pick a desired A/F ratio for the engine to remain at.

For more info check the DIY PROM board.

 

Nope, stock flow 19 lb/hr.

I also have a heavy foot, but still I don't understand why I get poor mileage, even with my heavy foot I should get something like you... or so I would think.

Sounds like I need to do some prom tuning... I really like the idea of burning my own chips, but I don't have any of the equipment, and I have little knowledge... I guess it's time for me to start buying and reading, see what I can do.

BTW I have a stock chip right now, and my engine is basically all stock. I have been running 20w50 oil, could that be cutting my mileage down this much?

Thanks Guys!

 

Have you changed your O2 sensor? I changed mine and the milage went up.
My 88 Formula is bone stock with 115K miles on her.

 

When I bought the car, the guy told me he just put one in. I believed him, because the one that's in there still looked shiny, and hadn't completely rusted over. I have another one, which a friend gave me, said he bought it, put it in, saw no difference, and pulled it out within a week. I tried to put it in, but I couldn't get mine out!

 

Do you have the special socket for the O2? makes it much easier to remove it. It has a slit in it for the wire so you can use a ratchet.

 

No, no special socket, I just took a normal deep socket, took the plastic part off the plug, coiled the wire up inside the socket and tried. I used a 1/2 inch braker bar, and the thing wouldn't budge. I have to oil it up with some wd-40 and let it sit a while and try again I guess.

 

WD-40 is crap as far as penetrating oil goes. PB Blaster is much better, and this stuff my father-in-law gave me called Sili-Kroil is the best stuff I've ever seen. It comes in an orange can and I think he bought it from Eastwood. I have used it to loosen stuck bleeder screws, brake lines, break dis-similar corrosion bonds, and a lot of other tasks that usually end up with a broken part when using anything else.

The blue wrench can also come in handy if you have access to it...

 

Hmm.. thanks for the tip, now I will just have to find some of the Sili-Kroil or PB Blaster.

Back to my gas Mileage.. any other ideas?

 

NAPA sells the PB Blaster. I think the Sili-Kroil may be mail order only. I'm fairly certain it came from the Eastwood Company.