foggysail

I am enjoying my new to me 1999 Taurus SE powered with the mighty Vulcan engine. Car has only 79K miles on the clock that I believe are original.

My problem--- it is getting about 20 MPG where as my older, retired 99 with a Vulcan consistently provided a comfortable 25+ MPG. The engine seems fine, no misfiring. Tonight I cleaned the mass air sensor with electronic cleaner but that is grasping. And my tire pressure is at 40PSI as it was in my old car and I installed a new air filter.

Now 20 vs 25 might not seem a lot but it is a 20% mileage reduction. Any thoughts??? Ideas?? Or is this just normal.........and I doubt it.

Thanks--

Foggy

tbird100636

40 psi??? That's high for that year. 33 psi is what the door label calls for. Make sure the Throttle body is clean too. Even though it's not at the 100,000 mi. yet you might want to give the plugs a look over.

__________________
Master ASE Certified L1 Chrysler Technician- still a Ford fan at heart.
1964 Thunderbird Hardtop- Chantily Beige- 390 FE 4V V8-Uncle's Car
1966 Thunderbird Convertible- Red- 390 FE 4V V8- Uncle's other car- waiting for paint and body work!!!
1967 Mustang Convertible- Blue- 289 V8- helping a friend re-assemble this classic

foggysail

Thanks T-Bird. Yes, 40 is a little high but the tires are rated for 40 so that is what I have ran now for some years. And yes, the ride is not a slushy as it would be with lower pressure. But again, I have kept the tire pressure high for both tire wear and better fuel mileage.

Throttle plate--- how dirty would that have to be to affect fuel consumption? I did look at the one in my other car and it was cleaner than I thought it would be. Also, I used lacquer thinner to clean it and again, yes I knew that it should not be used. But that was the other car.

What do you recommend to clean a throttle plate? And plugs--- I did pull one out and it was gapped (worn)about 100 thousand based on my non-calibrated eye. Plugs will get changed next week.

Foggy

tbird100636

It can have an affect on fuel consumption. The PCM will eventually adjust the IAC operation to compensate at idle, but it does result in slightly less airflow, the dirtier it is the less flow. You can use either spray carburetor cleaner or brake cleaner to clean, with an old toothbrush to scrub the tough caked on dirt. After removing remember to remove the IAC and the TPS. Getting carb or brake clean in the TPS will cause a check engine light and the engine will not idle correctly. You should be able to get it fairly spotless. Anything that won't come off with the toothbrush can be gently scraped off with a sharp straight pick. Clean the IAC as best as you can. After re-assembling, disconnecting the battery for 5 minutes to clear the adaptive memory. Re-connect and start the engine and let it idle 10 minutes. Take the car for a good drive.

0.100" gap?!? That would be no electrode left at all. But it's probably worn enough beyond the 0.042"-0.046" gap. When you grab a set of plugs, make sure to grab a plug gap gauge. Very inexpensive, wether a keychain round one or a straight pocket one. One other thing, check the date code on the plug wires if still the Motorcrafts. Over 5 years old is pushing it. I did the plugs only without the wires on the 01 Taurus Duratec I previously owned, and a week later I was pulling the cowl screen and coil pack again to do the wires because it developed a intermitent skip at idle.

__________________
Master ASE Certified L1 Chrysler Technician- still a Ford fan at heart.
1964 Thunderbird Hardtop- Chantily Beige- 390 FE 4V V8-Uncle's Car
1966 Thunderbird Convertible- Red- 390 FE 4V V8- Uncle's other car- waiting for paint and body work!!!
1967 Mustang Convertible- Blue- 289 V8- helping a friend re-assemble this classic

foggysail

Thanks TBird!

Foggy