QuestionI have a 02 Oldsmobile silouette with a 3.4 L engine.Late last summer we had the intake manifold gasket replaced due to coolant leaking into the engine(this info is just for history sake). A few months ago I was looking at the Drivers Information Centre and noticed that my fuel economy had dropped eg. at 85km/hr i used to get 30mpg(6-7L/100km) now it has dropped to 24-25 mpg at the same speed.The only time it gets up to 30 mpg anymore is if I have a wind at my back. There is no engine light or codes, starts fine, doesn't seem to be running rough or any hesitation. Air filter has been recently changed. I'm wondering if it could be a O2 sensor!? You're thoughts?
AnswerHi
This is the BIGGEST problem I run into. There are ALOT of varibles, as you know....wear and tear on the engine, engine loads while driving, weather, tire pressure, etc.....
Have you had any aftermarket DVD player or such installed?
Is the tires properly inflated? Different driving conditions (more city lately?).
I would FIRST, if you want to replace any parts, I would recommend a GOOD major tune up (Plugs, Plug wires, Fuel filter, Injectors power flushed, induction service) Then drive see if it improves.
That would be my first advice....see what happens.
I Hope this helps
Follow post back, if needed.
Pawl
