I'm having issues with my 2000 Sunfire GT. Its been pretty cold for the past few weeks (-25'C). Lately my car hasn't been starting when its outside. yes its been PLUGGED IN and the block heater is working. The problem is it won't fire. As i crank it over it will "stumble" but never start. If i push it into a garage and leave it for a day or so it will start right away. These are classic "water in the gas" symptoms so i put a bunch of gas line anti freeze in (methyl hydrate). That didn't help. So i changed fuel filter. No go. I've even changed the fuel rail and injectors with a spare set to no avail. As soon as i leave it outside overnight it won't start and i can't have it in the garage every night.

Is it still freezing up or could it be something else? Fuel pump? Ignition system?

I'm going to try to get the fuel pressure tested and check the spark.

Its a 2.4 with light mods... exhaust, header, 2.2 coil swap, AFPR, etc.

Any help is appreciated

I have the same exact problem. I was told to try the dry gas , didnt work either, see below for what i have and what i have done, still spits and sputter when I start, if it starts.


I have a 2003 Cavalier auto with 132,000 miles on it and have some issues lately.

Here are the symptoms all during a cold start after sitting overnight or long period of time:
- starts, idles rough, misfiring, at least that what it sounds like, for the first 5 or 10 seconds of startup
- starts, idles rough, then stalls, normally takes 5 or 10 cranks to start, one day it never started and I killed the battery, started once I jumped it.


Things I have replaced in the last 500 miles to try to fix the problem.
- fuel filter
- injectors
- plugs
- spark plug boots
- coolant temp sensor
- fuel pressure regulator

Things I have replaced at 80,000
- Fuel pump

Diagnosis

the only thing I have checked is fuel pressure, this is by turning just the key on, not starting it.
50 psi when cold
54-56 when the car is warm and been driven.