I have an '05 sunfire , with terrible fuel mileage. Bought the car, wife drives it most of the time, changed to mobil 1 5w30 synthetic oil @ 2400 km, added K&N drop in filter. Was getting awsum fuel mileage then it seemed like just overnight the mileage went way down. The car is not being driven any differently then before, nothing else has been changed. Tire pressure is correct, etc....... The car takes forever to warm up, then cools off rather fast if I let it idle. They have changed the t stat, with the same issue still remaining. It will warm up on the highway but cools off fast once you get off the highway. It does not warm up when being driven in town if the temp is below 0c temp gauge sit a tad over half way. I can get the temp up to 3/4 if I drive it like it is stolen then let it idle for a few minutes and it drops again. It smells very rich at the tailpipe which is also very black inside. The car lacks the power it used to have and the fuel mileage absolutly sucks. I have had it a dealership that refused to look at until it set a code, I unplugged the IAT sensor wires and it did not turn the cel on, is that normal?? They after seeing that put it on the scan tool that told them it was unplugged but still no cel.
Plugged it back in and they said it was fine, and if they siad it was good its good. Dealership 2 had it overnight, checked it out said everything is fine. They understand that I am having poor economy but do not have an answer as to how to fix it. Last 3 tanks of fuel have been as such,
1. 153 km= 33 liters
2. 148km = 31 liters
3. 225km=40 liters
That is absolutly terrible, my tbi 350 truck does better. What could cause this problem? I am at my wits end with this car..............................
You're running rich, it sounds like. TPS isn't a pollution control, so the CEL isn't likely to come on. More than likely you would be getting poor performance 'cause the engine can't know what you're asking of it (can't know if you wanna haul @ss or cruise by way of the throttle position), so it assumes a single cripple mode/ generic operation.
Would not a faulty primary o2 sensor set the cel? I have also read here that the fuel filter may be causeing the problems? My ? is how does that pertain to poor economy? Any other ideas or suggestions would be appreciated.
A bad 02 sensor will not always throw a code. I don't know why people believe that if you get a code, something is wrong or that everything is fine untill you get a code. A code is just an error like everybody does. It comes up when something was not like it was before. An 02 sensor can be bad with no code and give you horrible gas mileage. If you really want to know if the 02 sensor is wrong, unplug the 1st one and drive it like that. No the car will not run worst, if you think that it's because you don't know how the Ecm work in our cars(I'm not aiming at you Shawn, it's a precaution against other people).
2nd, the temps is NOT suppose to be over the half mark on the temperature gauge. If it get over that, it's too hot so that part of your car seem's normal unless you want your engine to last under 200km and running in the 200°+.
Gilles
2.3 Ho
you should expect at least 26mpg in city driving and 30+mpg for highway driving to give you a benchmark.
aprox. 42km to 4 litres city.
and 48km to 4 litres on the highway.
Either way the car should not have mileage that poor under any circumstances, my little brother has a supercharger, and still gets better mileage.
-Chris
If you bi*ch enough to the service department about the fuel economy they will put it on the diagnostic computer...I know this because I almost had to do it with mine....
I had them convinced to do it until I found out that around 400-450km per tank is normal.
Trust me...If you complain enough and keep going higher someone will give you satisfaction...just to shut you up.
"I know not with what weapons World War III
will be fought, but World War IV will be fought
with sticks and stones."
-Albert Einstine-
Yea its only 8 months old, plenty of warranty. I keep gettin told that until it sets a code there is nothing they can do about it. They had it on a scan tool and told me there is nothing wrong with it. It used to do well over 450 km per tank in town, then one day it turned to crap. Nothing has changed on the car, gets driven the same way etc.... I can am not concerened with a small loss due to cold weater but this started when it was still warm, and continues to get worse, what happens when it gets to -20? I have complained about it many times but get the same answer- no code= no problems. I see no reason why I should have to start replaceing parts on a car under warranty with 11,000 km on it. Thnx for the suggestions any more would be appreciated.
sounds like you may have a bad coolant temp sensor for the ecu. that will make the car run rich. also clean the IAT.
see ya!
