I have a 2000 Durango with a 4.7L engine and 148,000+ miles. I drove it on Thursday, no problems. Didn't drive it Friday. Saturday morning it started, then immediately died. started and died, started and died. It would run as long as I kept the rpm at 1500-2000rpm. Left it sit all day and when I tried it Saturday night it started and idled at 800 rpm just fine. This morning ... Started and died, started and died, etc. Any ideas? Cash is short so where to start would be really helpful.