...but I have to brake with my left foot while easing up on the gas when coming to a stop, all the while keeping the revs above 1000 rpm.
This sounds like a seperate symptom then what the title of the thread says. If you are experiencing both
hard starting and
idle problems, then you have to consider a faulty IAC valve.
Also, a few years ago my 4.0L had very similar symptoms, it would not always start when warm and a poor idle, and the problem turned out to be a faulty ECT sensor. It took about a week or so before it threw a code.