Smell gas out of vents when A/C is turned on

What is the best process to check if the fuel injectors are leaking? Someone also told me to remove the fuel rail cap. If fuel is present when removing the cap it is the fuel rail pressure valve.

Found out the leak was coming from the test valve on the fuel rail. I replaced the schrader valve in the fuel rail. It stalled out today and got a code 33, MAP sensor or high circuit. Just kept cranking but would not start. Also been having rough Idle awhile ago. Could it be a bad MAP sensor? They never really go bad much. But got a code today and just cranks now.

I also checked all vacuum lines and they looked good. Some near the MAP sensor to fuel vapor canister solenoid along EGR were replaced before. So It is not a vacuum leak.

What is a good reading for a map sensor? With KOEO and KOER?

I did check the MAP sensor, it looks like there is an electrical fault with the sensor itself. Followed an step by step procedure applying vacuum to the sensor checking source voltage. The reading I got did not match in specs, plus it did not change. It stayed the same when applying vacuum to the sensor. Here is a step by step procedure I followed with the issues I am having:

Symptoms Of A BAD MAP Sensor
The two most obvious symptoms of a bad MAP sensor is that the check engine light will be shining nice and bright and that the engine in your vehicle will idle very rough.

These are some of the other symptoms your GM 2.8L, 3.1L, or 3.4L car or mini-van will experience with a BAD MAP sensor:

The check engine light will be on with a MAP diagnostic trouble code (DTC) stored in the computer's memory.
If your GM 2.8L, 3.1L, or 3.4L car or mini-van is 1994 or older, you'll see DTC's:
33: MAP Sensor Signal Voltage High.
34: MAP Sensor Signal Voltage Low.
Your vehicle won't start or will have a long cranking time before it starts.
Black smoke coming out of the tailpipe along with really BAD gas mileage.
The engine idles rough when running and has a lack of power when accelerated.
MAP SENSOR TEST 1: MAP Sensor Signal
How To Test The MAP sensor with a multimeter (GM 2.8L 3.1L, 3.4L)
The MAP sensor's job is to measure the amount of vacuum in the intake manifold. This vacuum measurement is converted into a DC voltage signal that can be easily tested with a multimeter in Volts DC mode.

I checked to see if the MAP is able to produce a valid MAP signal as I apply vacuum to the sensor with a vacuum pump, regarding the three possible test results and at the bottom of the test steps I've done.

Note: You do not have to use a vacuum pump to test the MAP sensor. You can use your mouth to apply vacuum to the MAP sensor (via a vacuum hose). The difference will be that with applying vacuum with your mouth you won't be able to bring down the voltage to 1.1 Volts. The important thing is just to see the voltage go down and then go back up (to its original value) when you apply vacuum with the †good ole' lungs’. ( I used the tool, not my lungs)

1
Disconnect the MAP sensor from its vacuum hose. On your specific vehicle, you may have to physically remove the MAP sensor from its mounting to disconnect it from its vacuum hose.
2
Connect your vacuum pump to the MAP sensor's vacuum nipple. If you had to disconnect the MAP sensor from its electrical connector to remove it, reconnect it to it now.
3
With your multimeter in Volts DC mode probe the middle wire to check source voltage).

Remember, the MAP sensor must remain connected to its 3 wire connector.
4
Ground the BLACK multimeter test lead directly on the battery negative terminal.
5
Turn the Key on but don't start the engine. At this point your multimeter should register 4.7 Volts DC.

Now, pump the vacuum pump to apply vacuum to the MAP sensor. The multimeter should register the following voltages at the following vacuum values (they may differ a little on your specific 2.8L, 3.1L, 3.4L GM car or mini-van):

1.) 0 in. Hg. 4.7 Volts.

2.) 5 in. Hg. 3.9 Volts.

3.) 10 in. Hg. 3.0 Volts.

4.) 20 in. Hg. 1.1 Volts.

Repeat this test step several times and each time, you should see the same values on your multimeter.
OK, let's take a look at what your vacuum pump test results mean:

CASE 1: Your multimeter registered the indicated voltages as you applied vacuum: This means that the manifold absolute pressure (MAP) sensor is good and not the cause of the MAP sensor code or problem on your GM 2.8L, 3.1L, or 3.4L car or mini-van. No further testing is required.

CASE 2: Your multimeter register voltage, but it did not increase or decrease as you applied vacuum: This confirms that the manifold absolute pressure (MAP) sensor on your GM car or mini-van is BAD. Replacing the MAP sensor will solve the MAP code issue (P0106, P0107, P0108 or 33, 34)

CASE 3: Your multimeter registered 0 Volts: This usually means that the MAP sensor is fried. To be absolutely sure, I suggest confirming that the MAP sensor has power and ground. If both (power and ground) are present, the MAP is BAD.

Now regarding with CASE 3, Both, Power and Ground was present and the wiring was ok with the connector tight. But regarding with CASE 2, Source voltage wasn’t in specs with the readings above and due to my testing I found out the readings were off they weren’t anywhere close to specs when testing it several times. Plus, The part is original too. So it’s got to be far gone by now.

Okay, sorry for the confusion. I just replaced the map sensor. The new one works because I do not have anymore engine codes. Right now there are not any codes active. It just keeps cranking and when I try to get it started it just shuts off. I also tried to check for fuel pressure at the rail. With KOEO there was nothing, when cranking there was nothing. The needle was not raising. It just staying at 0. So than when I connect the scan tool, I started cranking again and the fuel pump got 12 volts. The fuel filter was replaced recently so that should not be clogged, I also use good octane fuel, the fuel lines were also replaced recently too. The fuel regulator is still original but it is not leaking. I also know that the fuel pump relay is good because I put a new one in, just still cranks. So I just put the old one back in. I did research and it said sometimes you will not get any fuel pressure if you have a low battery. Do you think I should do a state of battery and charging test to see if the battery has a low charge? I been having issue with interstate batteries not lasting long, so I would not be surprised if the battery tests bad.

Danny, I do have one and in the paragraph I mentioned that I tried to check fuel pressure but the fuel gauge was staying at 0. With key on and cranking needle was not rising and I know it is not my fuel gauge because I have seen videos with the same thing happening. I also know the pump is getting power because the scan tool said so while cranking over the vehicle, it read 12 volts. Could a low charged battery have anything to do with it? I am going to check if it is charged. Just wanted to know if a battery could do that?