Dog Blacks Out

Okay, so, I have scoured the depths of the internet and I feel it impossible that NO OTHER DOG OWNER EVER has experienced our problem. I don't know where else to go, if this isn't allowed, feel free to delete. Our fur baby Apollo is the most precious thing in our lives right now. He's our heart and soul. He's also one of the most well behaved dogs I've owned. Until he thinks he's going to get into a car. It's like he blacks out. He is not responsive to commands, yelling incoherently, the measly assult that is what happens when I try to physically restrain an 85 pound dog. He has a no pull harness that worked WONDERS. He couldn't pull me anywhere. Well, he knows how to get out of that now. He just turns backwards and dances on his hind legs. I had a 10 minute battle with him in my new front yard today, where he pulled me to the ground and fought me with every ounce of strength I could muster. Like I said, he blacks out and is unresponsive to any type of motivation at this point, so I'm not interested in any more training programs. We have tried to desensitize him and it has not worked. I'm almost 18 wks and I cannot afford to deal with this, but I refuse to give him up. Does anyone else have this problem or suggestions? Our next resort is an ecollar. 😔