Had a call tonight on a gmpo75-3 Goodman.Homeowners claimed there furnace had a bad blower motor and needed it replaced but didnt know what brand it was .Went out an looked at it and it had a burnt hot surface ignitor. I didnt have the right one with me so I stuck on one of my 41-408 uniline that I use for a lot of rheems. I know its not the one I really need but I wanted to get them some heat being its a weekend and it is pretty close physically so I put it on to see if it could get me by till monday when I can get the right one. I did notice that a few times that it didnt light the burners on the first attempt of the ignitor but it would light after a few atempts. I guess my main question is their that much differance in all of the ignitors that you cant use some of them in differant applications? And if that most likely why it didnt light the first time everytime. I will test my gas pressures once I put the right one on. If that is so does everyone carry a huge assortment of them? After I got back tonight I looked to see if I could find the ignitor # I need, looks like a L38-046. I also see a L39-089 for Goodman too but thats not the one. What I have to carry all of them lol.