I've tried searching and couldn't find anything with this exact problem. I have an 87 ETA 5 pseed, all stock. On hot days (90's and above), when you first crank it it will only idle at 500rpms and sound rough. It takes a few minutes of idleing to come up to 750rpms and runs fine after that. If I start driving right away it will die when I come to a stop if I don't give it a little throttle. On cooler mornings (85ish), on first start up it does like it's suppose to and idle around 1000-1100rpms and come down to 750. I have always let the car warm up for a couple of minutes before driving it. I don't know if it's the heat or humidity affecting it but would like to fix the problem. Fuel filter is new and intake accordian boot is good. aAny other ideas. Once again on seems affected by the heat. Thanks.