Ferret makes a portable 5 gas analyzer, I have one but it was expensive, and requires sensor maintenance. I used it bunch when developing may EFI system.
I tried to find info on these after seeing your post and the ones I found ranged from $1700 to around $5000. I'm not sure if I was looking at the correct units, but the low side of that range is still way more than I'd like to spend. I didn't read the details about them after seeing the prices but is there anything in particular about them to justify the expense? Thanks.