Engine vibrate i have galant 2003 the problem is when the car is at D the engine shak espically when the A/C is on

How many times are you going to post this? Check coolant temp sensor.

Check for a shorted spark plug ie. touching central and side electrodes.

4 or 6 cylinder? you say "heads" so I assume its a V6? A interference engine does NOT require a new engine. unless upon disassembly there is severe piston damage. A 2003 Galant isn't going to be worth putting in a $ 2500-3000 new engine. A car that has had scheduled service usually doesn't break the belt, its replaced long before that happens. Yes, you can take the heads off and get it serviced, new valves etc. On a V6 you also want to replace the water pump.

The Galant has an interference engine, when the timing belt breaks the valves stop and the pistons strike them. At the least you need a new head. There is really no way to tell how much damage was done without tearing the engine apart.

Most timing belt suppliers recommend 50k to 60k miles for replacement. Your Galant has a interference engine meaning that if the belt fails your will incur major engine damage up to and including replacement of the entire engine.

So if you have over 60k miles on the car go ahead and change the belt, and while you have it apart replace the water pump.

vibration when braking is cause by warped rotors. have rotors turned.

please localize water leak for recommendations.

if your indicator lights aren't working, check the connector in the back of the instrument panel.

Every 9,000 miles ( 14,000 km) and there is no need to flash the engine, just get the engine specified by the manufacturer.

Just behind the aluminum valve cover...where you pour in your engine oil.

Several things can cause a vibration problem. Some simple things to look for espically if anything has recently been done under the hood. Check all plug wires or connections to fuel injectors and any vacuum lines to insure all is secure. Make sure have clean fuel, possible water contamination and check for clean engine air filter. It is really too new to have broken engine support but possible defect. This can be checked by going through the gears Forward/ Reverse and appying slight throttle in each with an observer. The engine should not ride up excessively.

I had the same problem with my 1995 galant, and I changed my idle sensor. note!!! you have to have it adjusted also.