bought my 03 coupe AT in Feb 09 I have 73K miles on it, was getting decent gas mileage then this winter started to only get 20mpg (mostly in town) only slightly better hwy, I changed plugs in Jan and now only up to a whopping 24 mpg hwy and I am pretty easy driving. on my 01 Z24 manual I would get 28 mpg at worse driving it like I stole it, I did the throttle body cleaning on that yearly. Wondering is there something similar to do with the ecotec? or do I have to suck it up and take it in. I will be the first to admit I am pretty ecotec ignorant but 23 mpg sucks. OH I changed fuel & air filters in the fall...just have a feeling fuel system was not the most cared for by previous owner
Its all about the pain...The Jewelry and Ink are just souvinirs
I bought some super concentrate Techron for my Cobalt and it went up from 30.5 mpg average to 32.4 mpg average.
Also, check the tire pressure, gas cap, vaccuum leak, dirty air filter, fuel filter, any wheel parasitic drag and so on.
The wife's Sunfire has the exact issue as you. I replaced the O2 sensors, Sea Foamed, new oil, plugs, a new axle and hub.
It went up 1 mpg from 25.
I thought it would be much better than this. She gets 26mpg, when she used to get 29.
I also pondered the timing chain. It has around 120k miles on it. It stretches and causes a timing issue, and I pray it does not snap.
It just costs so much for one, and I am always broke.
You sound like you need many small maintenance items done immediately.
My wife's 2003 Ecotec 2.2 liter Sunfire:
* 2 1/4 inch in and dual 2 inch out muffler Trans Am muffler
* 2 1/4 piping to a very long 2 1/4 inch resonator
* 2 1/4 inch catalytic converter
* an AEM true cold air intake NOPI edition
* 8 gauge ground wire kit
* Toyz front strut brace
* Russell stainless steel brake lines all around.
if the 02 sensor is going wouldnt it code out? I guess my Z24 spoiled me..had it 8 years changed oil religously, did all my regular maint. and aside from a alternator and a fuel pump drove her 255,000 miles with no issues and still ran like a champ when I traded it in.
Its all about the pain...The Jewelry and Ink are just souvinirs
