Hey guys, my 5 speed cavalier has this weird problem where if I go to reverse out of a spot, as soon as I put the clutch in to shift from reverse to first it will bog down and stall, it will then take a second or two to crank and seems like it's running rich afterwords. The next couple times I come to a stop sign the idle will stumble but then it drives fine for the rest of the ride. Today at work I even started it up and let it warm up before leaving and the problem was still there.

I've cleaned the throttle body, replaced idle air control, fuel filter, fuel pump has 10,000 on it, coils, plug corks, plugs, coil housing, upstream o2 sensor, fixed all exhaust leaks, map sensor, and some other small things.

My first guess was the fuel pressure regulator but there was no gas coming through the vacuum line port so I'm assuming it's fine.. Can these regulators fail without having gas flow into the vac port? Any ideas? Thanks