chitown928s4

When I bought my 951 I was averaging better gas milage than my NA about 430-440 from a tankful. That included some speeding of course. The past few weeks the milage has dropped to 280 a tank. I've checked cleaned my air filter and checked tire pressure. Still 280. What should I be looking for. The weather has gotten cold and I switched from 15-50 to 20-50. Would oil effect gas mileage. I understand the car idling to warm up but I can't beleive I'd be wasting that much gas idling.

swimmingly

vacuum leak? check your vacuum system with a gauge

if that checks out well, then check your FPR by hooking a gauge up to the fuel rail

if that checks out well, maybe you have a fuel leak somewhere.

sharky47

Plugs, vacuum leaks, tire pressure, O2 sensor.

racer

1) Has your driving style changed? (ie less highway and more stop and go?)
2) Have the air temps gotten cooler?
3) Have they changed over to "winter" gas where you are?
4) Why the change to 20-50? Especially as it is getting cooler, you likely should have swapped FROM 20-50 to 10-50/ 10-40. What is the recommended oil for your car? (hint, check owners manual)

Just some other things to consider...

Scuba Steve

My mileage dropped when the rear calipers stopped sliding so well. No noise associated with the problem.

95Juan

clogged cat can do it.

i had ~300miles to 15gallons. even with a bad 02 sensor, i was at like, 280-290 for 15 gallons.

put in the cat for smog?

SHWOMP.

250 miles to 15 gallons. i'm getting like, 14 mpg right now.

is it also noticeably slower?

Campeck

o2 sensor.

Mike C.

I would guess O2 sensor as most likely but thicker oil isn't helping with colder temperatures. I run 10W-30 Mobil 1 in the winter (daily driver) with no oil pressure problems.

wi54545

Go to autozone and find a Bosch o2 sensor for a 1990's Ford Taurus 3.0L. Then Crimp your connector onto that sensor. Around 40 bucks, or you could disconnect the sensor altogether and see what your mileage does to help troubleshoot.

ibkevin

If you pull the O2 and the tip rattles... odds are good you just found the problem.

skene

Last night I found out my TPS got unplugged somehow. That killed my mileage for the last tank and a half and gave me funny idle issues. Just another option to check.

ibkevin

If your TPS is unplugged, you shouldn't be able to accelerate.

skene

No problem accelerating and the car was surprisingly smooth with it unplugged. The only thing that was off was the idle and the car running rich.

bearone

it'll accelerate, just not very well.

it's a good way to troubleshoots the tps. jerky acceleration could be carbon tracking.

i used to remove it with a sharpened eraser until it finally needed to be replaced.