95 Firebird 3.4 slugish, "if it does start", next time its running great till warm, then wont idle, shakes till it shuts down. If you get it running, dont stop or slow down, you may never get it going again!

We bought this vehicle 30 days ago, it has been towed 5x since we got it. they have
accused us of flooding it, making problems up, till they themselves couldn't get it
running. It shows no codes at all. They have replaced the plugs and said they were
wet, when checked the next time it shut down, and it wouldn't start, they were bone
dry.They are responsible to make it run, but I cant keep getting it towed every day
they give it back. When they do give it back it runs fine, for less then the day.

I think the fuel is not making it, or is not consistent, It does pop out the intake, when it
is in the no start mode, but not like a true backfire.

I think I will end up having to pay to do the work if I ever want to get the car on the
road, So your suggestions are greatly appreciated.