91 Cougar idle/coasting a little fast

My 91 cougar/LS 3.8-liter V-6 has been great since I got it a year ago, However a few months ago my car started to idle really hard, up untill it didnt idle at all intill it was warmed up then it ran "OK" putting it mildly.

There where no check engine lights at all. So here is what I did.

- Cleaned the throttle bore (VERY dirty)
- Cleaned the IAC (was pretty dirty)
- Replaced the throttle body gasket

After doing all that the car ran great on idle. Now I do not have a tachometer on my car so I did not notice at first. But the car was idleing at 1500-2000 RPM I would say however it would not do this when I first started up the car it seemed to idle normal 600-800.

So it would idle fast only after driving it and putting into park/neutral. Im sure it idles at 1000k when in drive I just cant really tell.

So I was like oh sure a vacumme leak no biggy I took everything apart again and put it back together. No hissing at all, did a check with soapy water turned up nothing.

So I checked the senior check engine light to see what codes I get, here is the results.

327 - PFE sensor above self test minimum.
121 - TP sensor out of range or somthing

121 is not that big of a deal because that was me readjusting the idle screw. This is retoricle because it was doing the fast idle/coast thing before I messed with this

327 - Possible EGR problem however I find that strange that it would not report this untill after I cleaned everything up. I will consider replaceing the sensor however I dont want to waste 50$ im def not ritch.

the car does great at idle and everything now. But will idle and move up to 40 mph without even touching the gas and when I get it to 50 will maintain 50 mph without even touching the gas.

This issue has been quite frustrating, so I will give kudos to any who can shed some light on this long frustrating problem!

Thanks in advanced