i looked around the forum and couldn't find anything, and i was replacing my oil and i some how lost the plug. I dont know anythingabout the plug size as in if there different for different years but if it helps its a 89 mustang lx 5.0 thanks for anyones help

 

go to any auto parts store they have the correct one for a few dollars. will probably be 3x more at the stealership

 

89 5.0 ....You'll need a 1/2 X 20 MM plug.