Gas Mileage

Hi, i have a 94 3.0l plymouth voyager with 158,000km and i have been
starting to get really bad mileage. i can only get like 270km in a full
tank of gas. Can someone give me some suggestions on what kind of problem
its having.

 

If you are in an area that mandates MTBE in the gasoline (for air quality)
this could be the cause.
If I use fuel that contains MTBE during the cold winter months I see as much
as a 20% drop in mileage.

Of course other things to look at would be PCV Valve, O2 sensor, dirty air
filter and such.

Have you pulled the codes to see if they reveal anything?

 

Any codes set? If not, my first guess would be O2 sensor, but it could
be any number of things. My Chevy truck had this problem and it never
set a code. Turned out it was the coolant temperature sensor and the
engine thought it was cold all of the time and provided a rich mixture
as during a cold start.


Matt

 

This happened on my 89 Acclaim 3.0L - turned out to be a broken thermostat -
code 17 was set (staying in open loop because the engine temp didn't rise
within a certain period of time). Easy to put in a new one. Good luck.

bob

 

When was the last time it had a good tune up ? My 88 3.0 New Yorker does
better with fresh filters and plugs, and rotor and cap. Also check for EGR
issues and open vac lines to sensors ?
Is your tranny slipping? Carrying alot of dead weight all the time ?

Just places to start

Steve
88 New Yorker 3.0 - 32 mpg hiway with a tail wind