just yesterday I put in a set of yellow top 4 spray ford injectors into my 91, they are 19lb. the Tj's run a higher pressure compared to the yj's I think around 49 psi, I don't remember completely, the yj runs around 31. but same basic principal, a 4 spray injector is superior IMO to a single spray, better atomization of fuel. I noticed a slightly better idle and smoother acceleration. nothing to amazing but every little bit helps. This swap with a 4.0 TB brought back some life I felt like I lost after my lift. hope that helps