when I put the ac stick on hot ( or the red) theres loud shhhhhhhhhhhhh sound, And I dont Know where is this coming from, Is it a vacumm leak?, also my car backfires alot after I run the car for abut 10 minutes it stops backfiring, the backfiring happens all the time no matter where the ac stick is hot or cold.

Can somebody help me Im really confused.

 

you check the vacuum or the timing? You can buy little kits for 20 dollars with a vacuum gauge, timing light and tach.

See if the vacuum is stable and check your timing.

The ac should make a sound when you move the control. How loud is to loud? Got me.

 

yeah its very loud, It did'nt sound like that before I have own the car like for 4 years and that soud started like 3 weaks ago

 

also when I acelerate the shhhhhhhhhh stops, if I keep the foot out of the accelerator the sssssssshhhhhhh continues

 

Sounds like vacuum then. When you floor it vacuum drops to zero.

Get a vaccum gauge and check it out. Should hold a steady 17-18" (at least).

Of you could temporarily disconnect the vacuum soure to the heater box under the hood, (plug the line) and see if it goes away.

 

I get a hissing sound, its from the back side of the ac/heater control. The rubber hoses are fitting perfect, and I have to give a slight tug on them to shut them up. But this is easy when you dont have a radio in the dash