I have a 99 Accord EX-VL V6, AUTO, 91k. Well I bought a new car about 2 weeks ago and the honda hasn't been started in the past two weeks, well I just went out there a little bit ago because I was wanting to drive it around a little. Well when I first started it she started ok but after about 3 or 4 minutes of letting it warm up(it is also about 25 degrees here and snowed earlier) it starts reving to about 2000 rpm then back down to 1100 or so rpm and just keeps on doing that over and over. When I put it in drive you can feel it trying to pull away when you have the brake on and you can hear this kind of clicking sound thats not normal for it. Do any of you guys have any idea what's wrong with it?

 

IACV valve or thermostat problem is my best guess