Never had this issue before but I just started my vehicle and the tac automatically revved up to 1500 rpm when I cranked it. It didn't go back down while in park, it basically idled at about 500 rmp higher than normal. I put it into reverse and it jumped back down to normal speed. When I put it into drive it was fine. When I put it back into park it jumped back up to 1500 rmp, I put it in neutral and it did the same thing. So I put it back in park and shut it off. Interestingly it rolled forward a lot more than usual leading me to believe that it never actually went into park.
This 1998 Dodge Durango usually runs at 1500 rpm in 1st-3rd gear and around 1900 - 2100 rpm in overdrive. At idle it is typically running at or just under 1000 rpm.
So it sounds like a bad ass muscle car when it cranks now but this is weird and as I said, it's never done this before.
I put new tires on yesterday, the day before that I replaced the water pump and thermostat. It had a transmission flush a few weeks ago but it hasn't been slipping. I should mention that putting this thing in reverse has caused the vehicle to lurch a bit usually (but not always). Oh yes and there are no engine codes being thrown at this time.
Any advice/insight much appreciated.
UPDATE: just cranked it again and it functioned as normally... this is (for now) an intermittent issue.