Pontiac Trans sport'96 RPO LA1 fuel consumption

[Zebe9]

No matter how I drive and where I got 15.5 mpg.
Should I expect sth better from my Ponti ? Or is it OK ?(
I am a bit(completely that is !!!) disappointed 'cause still I expected min.17 mpg - City.
Highway much better of course.

Please advice !

PS.Filter,GM Top Engine Cleaner,both O2 sensors,injectors cleaning etc.
Is there anything to be done yet ?!

[Cliff8928]

The rated economy for the trans sport is 19 in the city and 26 on the highway...

I'd check and see if the fuel pressure reglator might have failed, that would sure cause a drop in mileage..


Cliff Scott
89 BerettaGT
89 Volvo740

[Zebe9]

Ponti TS'96 Re:Re

Can it(fuel pressure regulator) be checked without any
pressure measuring device ?

[geoffinbc]

Nope not really.
When was the last tune up including plugs and wires?
How many miles? It may be time to have thoes coils and ignition module looked at or replaced.

[Cliff8928]

Well, the typical mode of failure of a fuel pressure regulator on the MFI/SFI cars is that it will leak fuel through the vacuum port. You can just remove the vacuum line and see if there is any fuel in it.


Cliff Scott
89 BerettaGT
89 Volvo740

[Zebe9]

fuel cons. re

Thanx so far
Fuel pressure regulator does not seem to leak,I put even a condom( ) on vacuum line and reconnected to FPR for some 1/2 tank-looks no difference in mileage,maybe without it idles smoother....and no fuel evidence around neither.
I checked and replaced most things-except the coils,but how they can get used anyway ?!
The plugs and wires just replaced in autumn(some 2 kMiles ago)
EGR-checked&cleaned, IAT(intake thermistor) also OK.
Maybe stock fuel rating is based on 80 y.o. mom test drive ?
Still- 450 km/tank(20 gal=75L) is a MAX I can get from TS in mixed-CTY/HWY (15-20 Centigrade enviro temp and Very easy drive !

Really, guys-If you tell me "sorry-threre's nthing to improve,TS just is so" -then OK I can live with that,but.... I would REALLY would like to find that small 'doodah' that poisons my TS riding !
Still any reasonable suggestion very much appreciated !!

[Drenis]

I get 27 MPG in the city with my 3400 Impala.

And that's including lots of hard driving.

[Zebe9]

3400 & mpg

I get 27 MPG in the city with my 3400 Impala.

And that's including lots of hard driving.

Ohhh,Don't get me down !!
I got: Pontiac Trans sport 125 kmiles '96 3400, well maintained,everything checked/replaced on time, even decarbon made lately...With no heavy load(actually it does no matter how much it carries) and 15,5 mpg mixed(!) cycle is maximum I can get. Even scan tool shows no DTCs and 99,9% effective combustion.So what to do next ?
At least where/what to look for ?

[akira]

check your air filter and muffler/cat for being plugged? maybe have your injectors cleaned and tested. Is it running rich?

[dl]

Did you ever do a straight highway run, and fillup right before and after?

I do a wide range of driving from local NY city, to long vacation trips,
so I get a wide range gas mileage with with my Corsica 2.8 auto (non-OD)
a low of under 11 in local winter short trip, to a high of 28+ on a long summer vacation trip. your style and type of driving matters. that new oxygenated methanol fuel drops mileage too.

Dave
Brooklyn, NY