Ok, for like 3 months my stang has been running rough and dropped rpms to like 500 if I sat at a light for like 2-3 min. I had tried changing the TPS and the IAC, neither were the problem. I also changed my roter, distributor cap, spark plugs and wires....still no fix. So I go home one day and am determined that I'm going to solve this problem once and for all.

I open the hood--having the car running at the same time-- and try to see if I can locate the problem either by hearing abnormal noises or something of that nature. So I hear this hissing noise and just think it's just a normal engine noise, like the intake taking in air then I notice it's right under the intake it seemed. So I look but all I can see is to hoses one big one and one little one. I stick my hand in there to see if I can feel anything, I notice the smaller hose is a little beat up so I figure OK it's a worn but then I reach futher back and notice the hose has a hole in it right at the point where it's supposed to connected to a spout coming out of the intake. I put my finger in the hole and voila! the engine starts to run perfectly. It happend to be the vaccum hose that ran from the intake all the way to the airbox. So I spent around 300 bucks on a problem that only took a $1 piece of hose to fix.

Well it's running perfect now and I hope anyone that has this problem and can't figure it out will learn from my experience.

 

Nothing better than the feeling of finally fixing a lingering problem.