iateadonut

I just picked up a v6 automatic mustang; as far as I can tell, I'm only getting 10-15 mpg.

I just replaced the spark plugs with NGK V-Power. When I replaced my Grand Am with laser irridium, gas mileage went up for 16 to 20 (city driving). What will be best for this mustang?

I will check my air pressure in my tires tomorrow and install new spark plug wires. Any ideas on what else I should be doing?

The kid I bought this from had a CAI and dual exhaust installed. There's a sulfur smell - I'm wondering if this is tuned without regard for gas mileage. Do I have to buy an SCT X3 or can I rent one or otherwise have it tuned? Can I buy a used one or do I need a new one?

BabyGT

Sulfur smell generally is said to be a sign of the cats going bad

iateadonut

one of my tires was around 25 psi when it is max rated at 44; filled them all to 40; hopefully that will help. i've also replaced the spark plug wires.

i will get a tuner soon if that will help.

NYstang

If you have a cat going bad, you wont get good mpg at all. Youll need to replace the cat or find a new factory Y-pipe. Also, you have a 4R70W, not a AODE

BabyGT

I'd spend the money investigating the cats, as a tuner will do absolutely nothing to help mileage if they are bad.

Then you have spent 300ish for completely nothing.

massguy54

Bought an sct made car faster and better gas mileage however did a tune up and replaced everything before the new tune

iateadonut

You're right. Thanks.

Spark plug wire change and filling the tires with air seems to have made a difference. I'll update next time I am able to get an accurate mpg.

BabyGT

That's cool, but if his cats are bad a tuner will make absolutely no difference. Might even make it worse.

Mobiusone stang

Would y'all use factory cats or like flowmaster high flow cats as a replacement? (well at least for me I have a dual flowmaster exhaust...)

PNYXPRESS

Drop the air pressure down to what the placard inside the door jam says not what the tire sidewall says. 40psi is TOO high and after driving, the pressure could increase above the max pressure for the tire due to increase of temperature