Ok I have a stock 2003 Mach 1 that just cracked 100k miles. I went to get in the car today for work and it would crank but not idle. If I give it gas it will stay running with no problem untill I let off the gas and it just dies out. I put the OBD II on it it is throwing zero codes. I checked for vaccum leaks, found none at all. I changed the TPS sensor no change at all in the idle or lack of idle. I even pulled the PCV valve and MAF off cleaned them and reinstalled, again no change. I almost have my mind made up that either the sensor is bad in the PCV valve or the Idle Air sensor is bad. I have never seen a PCV valve with a sensor so I'm not sure what the symptoms would be when they go out. If anyone could be of assistance I would greatly appreciate it.

 

My first guess would be IAC valve. Don't clean it...replace it and report back.

 

^^I'll try this first.

 

Ok I did a full tune up and replaced the IAC and it idles fine now thanks for the help.