I have a 2003 Cavalier with about 150,000 miles. It cranks but won't start, fuel pressure is good and I can hear the pump engage when I turn the key (also replaced fuel filter, since its cheap and worth a shot), new plugs, swapped ignition control module and coil pack that I know works and still no good. It sat for about a month until I found out it wouldn't start. I went to move the car out of my garage one day and it wouldn't start, and hasn't since.

Background on issues before the no start condition. I stopped driving the car because the air would only blow semi-cold when I was on the freeway, at idle or at lower speeds it blew hot (I live in Arizona, I was only a couple months from the weather cooling down, so I was waiting until then to start driving it again). Also, it idled rough periodically, with an intermittent knocking sound coupled with a small surge in rpm at idle. Other than that everything was fine, no noticeable loss of power, no drop in mpg. Other than the ac and rough idle, it drove fine until I stopped driving and let it sit.

When I changed the plugs, one of the four was fouled, not sure if this helps with the no start condition but I thought it might explain the rough idle a bit. I also believe the fuel pressure regulator is bad, since I can smell gas in the vacuum hose, but from what I can tell, this wouldn't cause a no start by itself.

There was no check engine light when I stopped driving it, and it also throws no codes

please help!

 

What is your battery voltage? Does it have enough cranking amps? Or is it weak?

 

it can. Do a fuel pressure leakdown test to confirm the fpr or an injector is not leaking down.
What engine 2200 or 2.2ecotec?

 

Battery is good

 

Fuel pressure holds, I let it sit for a couple hours and it didn't drop a bit.

 

which engine?
theft light on?
if not;
confirm spark with a spark tester
do a compression check
check for injector pulse
check for crankshaft sensor signal
what did the fuel pressure measure?