[rakkasan21]

Hello I have a 1998 Mustang Cobra. I recently had a brand new engine from ford put in after the original was blown. Before the old engine was blown I had no problems with it whatsoever. The new engine ran fine for a couple of weeks so I had the ac recharged. The same day the ac was recharged I heard a hissing noise on the highway followed by an immediate noticable loss of power. After the hissing stopped it felt like the power came back. Now it runs fine for about the first 45 min and then it starts sputtering. I press the gas and the rpm will either drop all the way until i release it or it will raise but the car barely increses in speed. It will also shut off after I try to go after stopping at a red light. My father described it as "it feels like when the sparks plugs are missing." I know that isn't the case because it would feel like that as soon as I started the car right? Any ideas of what is wrong? Could the ac being recharged cause some kind of vaccuum leak? I would really appreciate it thanks.

[rich96cobra]

Sorry dude, you are being to vague. It is hard to diagnosis a car over the internet. I had the same symptoms when I got in a hurry, and forgot to plug in my mass air flow sensor!

My suggestion is to take the car back. If you paid them to put a engine in. They need to be responsible for repairing the car.

If the car is hissing, it sounds like the air filter lose, vaccum leak, etc. But then again, I would be guessing..... Any engine codes?

Take the car back. They could have left a number of things off.

Good luck