I have a 1987 Fiero V6 with 13,000 miles and when I start it for the first time of the day, it starts right up but the idle lopes between 500-1500 RPM. It has been doing this for over a year and of that year it has been in a garage sitting for 9 months. It doesn't sound like there is a misfire it just seems like the engine is struggling to stay at 1500. This only lasts for a few minutes. When I go to drive it, it runs great. Every time I start it after this, it starts right up and idles as it should, but if I wait a little bit while in park, it starts to climb to 1500 and drops 1000 and it just keeps doing this over and over again. When in drive, there seems to be no idle issues. It mainly only happens when air conditioning is on and is almost non existent when it is off. Sorry if this was at all confusing I just wanted to give as much detail as possible. I'm new here if you haven't noticed, but any help would be greatly appreciated. Happy 4th!