[quote=@Mr_pink]Uh yes he was.[/quote]
I went through every Avenger team on the Marvel Comics Database wikia and Deathlok was never once mentioned as a member or an ally of the Avengers. When was he a member also which various Avengers team?

Update: 
Earth-1298 has an Avenger team with Deathlok as a member. Which existed in comic form from October 1998 to June 2001.
[url]http://marvel.wikia.com/Earth-1298[/url]