My automatic is slow to change gear until it warms up only the first five minutes. Is it oil or intercooler

Auto transmissions are real sensitive to oil and flow issues. Not knowing your make, year, and service history, I will make the following suggestion. Have your transmission serviced with a Flush, filter change, and new oils. This should fix any flow issues that can cause this problem. If still an issue after that, you will need to have it serviced or it will fail in the long run.

NOTE: service facilities such as Oil & Go, have this flushing service available at a flat rate charge and I would use this type service rather than a transmission shop....but that is your choice .... hope this helps...
JP

What type of vehicle and transmission is this. But by the sound of it. It's acting like either you are having a trans fluid issue or a pump problem. But if it acts fine once it warms up then you sound probably have it serviced. But be careful how shops service your transmissions. For some crazy reason today shops down what they call servicing the trams when all they do it use a machine to suck out all the old fluid and replace it with new fluid. That's is a cheap and easy way for them to make a lot of fast money. The proper way is to drop the trans pan, remove the strainer filter, let fluid drip for over a hour, remove and replace old pan gasket, install new strainer filter, replace trans pan, and most importantly fill with the proper trans fluid type. It can usually be found on the trans dip stick. Also mistakes that many people make are filling the transmission back up when in park. The correct way to do it is to fill the transmission up almost completely with the correct amount while vehicle is in NEUTRAL GEAR while running. After that ensure you have the correct amount in trans by cycling through all the gears with the parking brakes on several times. Once the vehicle reaches normal operating temperature put back in neutral with engine running and parking brake set and check the fluid level to ensure the correct amount is being read on the dipstick. Then test drive and check once more. One thing I did leave out is. On most automatic transmissions drain pans there is a magnet that is located in the very bottom of the pan. When you remove the pan check the magnet. It there are large chunks of metallic material there maybe much larger problem. Anyway if normal, clean the magnet and reinstall in the pan before putting it back on the transmission. I hope this helped and good luck.