Do all 4.0 litre rev up to about 1500 rpm on start up when cold or hot? Mine does and then drops down to about 900 rpm after a few seconds.I change all the sensors and its the same.Is this normal?thks........
Mine does it. 1500 seems a little bit high, but my 93 deffinatley winds up a little when I start it. I don't remember if a 91 is EFI or carburated, that would make a difference too.