I have no brakes after installing new brake booster

I have a 2005 Mercury Mariner V6 with 4 wheel disc brakes. The truck has 120k on it and I have been having some issues as of late. The truck has had the hissing sound coming from the brake pedal and I was also having engine issues that developed around the same time. When I would depress and hold down that brake pedal the car would almost stall out and as soon as I released the pedal the rpms would raise back. The issue progressed to the point that without pressing the brake the vehicle would start to sputter and then(I assume) the computer would try to correct for the vacuum leak and the rpms would raise and smooth out. I purchased a Cardone remanufactured Brake Booster but the push rod was almost 2/3" shorter that the one that I removed from the vehicle and when it was installed the push rod caused the brake pedal to not make contact and kept the brake lights on. After more research I found that several people had this problem with the remanufactured boosters. So I stepped up and purchased a brand new Power Brake Booster from Berge Ford. I had called around to several Ford parts departments and provided them with the VIN and they were the only dealer in the valley that had it in stock. After the 85 mile round trip I installed it in my vehicle but the push rod going through the firewall seems to be too short and it too is causing the brake lights to stay on. I decided to complete the installation and hope that after bleeding the brake system the pedal would come back and close the brake switch. After I bled the brake system and test drove the car, the brake lights are still on and the vehicle has almost no brakes. The pedal feels firm but it goes all the way to the floor and the car will barely stop even at only 10-15mph. I am not sure if the push rod being too short is the issue or if it something else. Any thoughts?