It may be more simple to use the SimpleTimer to fire up a sequence to read the analog sensor, say, every 5 seconds. In the Blynk PushData example it’s described how to do that, it’s not very difficult and good practice to do timed things. BLYNK_READ and BLYNK_WRITE can be a bit tricky to understand at first, so that’s why I would go with the SimpleTimer solution.
I basically use the same method for lighting virtual LEDs ( I think they can change color now too, so you only need one LED!).
Does the pressure reading work fine? Because it probably set to Pull frequency of some time to get the value from the sensor, but the LED’s don’t do that.
Another solution would be to put the LED on/off sequence in the same VPin as the Gauge reading. It saves a Vpin that way anyway 
And that should definitely work better. Come to think of it, this is what I would do