cleaning out the fuel system

Seafoam is my vote. It has a long history and there are many on this site who will testify it has been a good product.
Not sure it is a cure for slow warm up, but if you want to clean the system is is a good choice.
I put maybe 1/2 - 2/3 can in my tank, idle it until it is quite warm (15-30 minutes) then shut it down and let it sit overnight. Then run the tank down with a lot of varied driving (some stable highway, some hard full throttle use, etc). Then add the rest of the can and refill.
The long idle gets the solvent in the idle circuits, and full throttle use ensures you get it on all parts of the slides and such.
Is this for the 1100?
But as for slow warm up- you might check and be sure the thermostat is operating properly. If stuck open it will take a long time to warm up.

I have in various vehicles at different times. It may or may not have done anything, I do not know. I do know the seafoam has made a difference before/after with several of my older rigs in the past. Not speaking against gumout, just 'voting' for what I know has worked. For me.