dubbed1500

i am having some problems and i am wondering what to do. when i start the car it makes a hissing noise so i checked the belt and the alternator and that is not the noise either. also when it is cold it misses out and some times back fires i have replaced the coils and spark plugs and wires. we have a scanner so i hooked it up and it had no codes and everything looked normal. so i do not know what is wrong with it because i do not know where to start if any one could give me some ideas i would appreciate the help i have only had the car for three months and it has been in the f**king shop four times and the trans is still acting up i would like to get it fixed because i like but it has been a pain. also it should not be having any problems in the first place it only has 11500 miles on it sorry for all the bitching but i am a little disapointed with it so far thanks for all the help </P>

Dan04COBRA

Hisses are generally caused by vacuum leaks, the intakes are prone to cracking on these cars. The backfiring is from unburnt fuel...something to do with your ignition isn't working properly.

dubbed1500

i checked the ignition system out and all the coils are working all 8 are getting good spark the coils plugs and wires are all new on the intake do you know where they normally crack at because when i take it to ford they say that they can't any thing wrong with the car if i could find the problem and fix it for not to much $$ i would but i am not going to sink much in to it because i am scared what will go wrong next