Edit *I've Realized I made a pretty hilarious typo in the title but unfortunately I cannot change it to say shift instead. Oh well.*

We have taken our problem to the mechanic a few times to no avail. As forewarning I do not know much about cars. I don't have any error codes to give you, and any detailed information might take a while to get conveyed as I talk back and forth with my mother. Here is what I can tell you!

My car is a 1999 Honda Civic Ex. I bought it used around 180,000 miles. It had a history of having failed O2 sensor that the previous owner attempted to replace when the check engine light came on. But it just came back on again afterwards. We did the same thing when we started having our issues, and after replacing the O2 sensor, it came on the next time the car overheated.

Here are the symptoms:
In hot weather ONLY, in a lot of stop and go traffic (highway driving does not yield same results) the car will start to have some minor break problems and the RPMs gage start going wild. While this is happening.if we go to park it, it will become stuck in park and will not shift into any other gear. RPMs go crazy even when the car is parked. The temperature read on the dash is normal, but upon just touching the hood we find it to be fiery hot. So we turn it off, pop the hood, and let it cool off for about 20 minutes. Once it's cooled, there is nothing left to do but drive it back home.

This happened on several occasions always on very hot days when we have been doing a lot of starting and stopping. Fluids all seem normal.

 

Pour some Laxative down the fuel tank, and take her for a quick spin around the block. Then let her sit for about 20 minutes to see if anything comes out the tail pipe.

If that doesnt help maybe change thermostat and see. If its hot weather related, or stop and go related it sounds like a over heating issue. It wouldnt over heat on the highway because theres a constant flow of cooling air across the radiator. While driving in city, stop and go. Theres not enough air passing over the radiator, and hot days makes this effect worse.

Its possible and not unheard of for water temp sensors to quit working. Theres no way anyone on here is going to be able to tell you exactly whats wrong, or what needs to be changed on your specific vehicle. But its more then safe to say with the info you have provided, your over heating. Now the cause of the over heating is what you need to find out. I said thermostat because they go out quite often, and get stuck open, closed, or in between. Hope this points you in the right direction. Good Luck!

 

You probably have several issues combining to make the problem. One may be the transmission cooling, or just that it is way overdue for a transmission fluid change. You can check the level of the fluid by pulling out the dip stick on the transmission. the level should be between the two marks and the fluid should not be cloudy or dirty when you wipe it off. Cooling lines run across the top of the transmission to the radiator. are they intact and not crushed or crimped?
There is also a plastic box with a transmission control unit under the dash near the gas pedal. That has a circuit that locks the shifter in park. There is also an electric servo and switch in the gear shift unit that physically locks/unlocks it in park.
Crazy RPMs sound like you may be describing an Idle surge. Check the FAQ on IAC and FITV if it is surging (racing up and down) and also check for vacuum leaks.

Keep asking questions and better defining what the problem is. It's all repairable. Most of all use the search and FAQ