Bad Gas Mileage

[03 VENOM]

I'm getting like 14 mpg. With no WOT throttle runs. Just cruising highway and city.

My mods are only 2.76 pulley, idlers, JLT Budget HP kit, tr6 plugs and a catback exhaust and a dyno tune from 7 years ago.

I switched my CAI from a K&N FIPK to the JLT. Could changing that give me worse gas mileage.

Now, I don't know for sure what my mpg was before the JLT but my I'm filling up alot more often.

I also had my fuel filter changed 500 miles ago.

 

[SVT_Troy]

The plugs aren't 7 years old are they? Getting the tune checked/retuned probably wouldnt be a bad idea. Also are you throwing any codes? Im wondering about 02 sensors to be alittle more specific......

 

[ZincSVT]

i got 160 miles last tank, and usually around the same almost everytime. these cars just suck for gas mileage

 

[03 VENOM]

Yes, the plugs are 7 years old but only have 3500 miles...No trouble codes come up. I even plugged my Xcal2 up to check.


Could I return my tune back to stock and drive it around carefully to see if it throws any trouble codes??

 

[03 VENOM]

i got 160 miles last tank, and usually around the same almost everytime. these cars just suck for gas mileage

Wow....that might be around 10 mpg :shrug:

 

[supman]

Gas mileage

^^^I get the same. Around 160-170 miles per tank. That's without any wot pulls.

 

[Sagittaria]

??? On highway I fill up around 280-290.. which is about 20-21 mpgs :??:

 

[SilverCobra7]

I'm getting like 14 mpg. With no WOT throttle runs. Just cruising highway and city.

My mods are only 2.76 pulley, idlers, JLT Budget HP kit, tr6 plugs and a catback exhaust and a dyno tune from 7 years ago.

I switched my CAI from a K&N FIPK to the JLT. Could changing that give me worse gas mileage.

Now, I don't know for sure what my mpg was before the JLT but my I'm filling up alot more often.

I also had my fuel filter changed 500 miles ago.

Did you go from a K&N fipk to a JLT CAI? You'll have to retune for the change! Moving the Maf will change the A/F ratio and tune.

 

[03 VENOM]

I didn't move the Maf. It's in the 12 O clock position for both the K&N and JLT.

 

[2fst4urtrk]

I only get about 200 a tank with fwy/town just freeway is Scotty 320 on a canned tune

 

[hotcobra03]

have you changed the gears?

i get less with 373`s 250-270 miles per tank...most of the time 12 gallons to fill

 

[05satinGT]

When I drove to get my tune I got 200 miles to HALF a tank. This consisted of not going over 75 mph and not once going over 2000 rpms. The other day I got 13.5 mpg, and I've gotten as low as 10 before.

 

[LETHAL03COBRA]

i got 160 miles last tank, and usually around the same almost everytime. these cars just suck for gas mileage

Agree, but I didn't buy it for gas mileage. :burnout:

 

[03 VENOM]

have you changed the gears?

i get less with 373`s 250-270 miles per tank...most of the time 12 gallons to fill

No. Stock gears. I'm gonna get a new dyno tune. Or at least put it on the dyno and check the A/F...

 

[01cobravortech]

I'm getting like 14 mpg. With no WOT throttle runs. Just cruising highway and city.

My mods are only 2.76 pulley, idlers, JLT Budget HP kit, tr6 plugs and a catback exhaust and a dyno tune from 7 years ago.

I switched my CAI from a K&N FIPK to the JLT. Could changing that give me worse gas mileage.

Now, I don't know for sure what my mpg was before the JLT but my I'm filling up alot more often.

I also had my fuel filter changed 500 miles ago.

Might be time to take it to a pro so they can datalog and see if something sticks right out. 14highway is way low. I'm asuming you drive witht eh windows up right? I'm at about 14 highway when I drive with the windows down. But I don't care.

have you changed the gears?

i get less with 373`s 250-270 miles per tank...most of the time 12 gallons to fill

You ever going to put a smaller upper on yours?

 

[fink46]

I would data log your o2 sensors to make sure one isn't on its way out. They don't have to be completly bad to set the cel off.
If while datalogging you see the volts on one of the upstream sensors not changing voltage on acceleration it could be shot. You want to see any where from .1v to .9v of oscillating movement up and down. I think you can use your short term fuel trims too. If bank 1 or 2 shows a way - reading its trying to accommodate the stuck rich o2 sensor.
I'm in the process of chasing down bad gas mileage too and just discovered this while datalogging the other day. You have to make sure your in closed loop mode before getting accurate readings on voltage though.

 

[Zacharyx]

sure your getting a MAF signal?? Saw a car a couple weeks back where the tune ran only off the load tables and got horrible mpg.

 

[03 VENOM]

Thanks guys. The car runs good. Would it run like shit if it wasn't getting a Maf signal or if an O2 sensor was going bad??

I'm gonna take it to a shop in Chicago to get checked out and retuned.