'99 Pontiac Grand Am - bad gas mileage - 14mpg

Let's see if we can nail this down :D

For starters, try an air induction service. I would try what I call an air induction service. There are other intake cleaners, I like to use castle hydroblast. You spray it into a vacuum line such as the brake booster line if nothing else is accessible. Full spray for 3 minutes, stall the engine with it or have someone kill it while your spraying. Let it set for a few hours then take for a short drive in low gear, revving the rpms to help break it up. First use Castle cleansrite to clean the throttle bore. Try to get the throttle plates scrubbed good with a brush, while your spraying. Use a rag to wipe the carbon out between brushings. Seafoam is another good product, but smokes a lot.

The 2.4 is a funny motor. How old are the plugs? When you replce the plugs I like to replace the plug boots as well, seems to be a problem more often that not. Be sure they are gapped right.

Other important factors: :idea:
Clean air filter :
How old is the fuel filter while we are talking maintenace? :
Look at the sticker on your door jamb for proper tire inflation and verify it is right? :

Take a look at your front tires-is there any edgewear? A bad alignment will cause resistance.
:idea:

Driving habits such as quick acceleration, braking at the last minute after going faster than needed. :Idea:

Now htat it is colder, is the car being warmed up longer than normal? :

Is the check engine light on : : very important to know.

Post your before and after reults, and we'll go further if needed :D

Wow. Will you come work for me? :Shock: :shock: :twisted: :twisted: LOL sorry paul, had to go there. Also to add. Gotta recommend a good tech to scan it for ya as your O2 may the cause of the excessive fuel consumption, map/maf performance also is a big factor.

Those quad 4's are a touchy little motor

Chris

Chris,
How's the deer hunting up there? Have to establish priorities first :)
What are ya payin?
I would think the CEL would be lit regarding the O2s.
That's why I mentioned If it was on.
Unless they are lazy? : :

1. Great hunting!
2. A buck two fifty
3. Nope
4. Could be lazy, biased or really fubar and trickin' the pcm

Biased?

I never thought those sensors were so opinionated :lol:

Now, what was the question?

Hey,
possible but not probable, I still recommend to get it scanned and get an accurate diagnosis. A common issue is a faulty or lazy O2 sensor. Let us know!

Chris

There is one before the cat or pre-converter. It takes a measurement of gases before it goes in the converter, and the the post converter measures the gases after the converter processes them.