rough Idle

[SIK99EX]

i hope this is where it belongs.I have a 1999 ford explorer. Anyway about the beginning of December my check engine light came on had it looked at. was just the bank 1 o2 sensor. today i took it in for a full tune up and the o2 sensor replaced. before then my idle was being really rough. acted like it wanted to cut off but never did. it fluctuated. not all the time just when i come to a stop or i was on an incline and whatnot. i noticed that the place i had the codes scanned had messed with other things. i noticed one day working on it that this thing wasn't hooked up. put it back on and she idled fine. went for a 5 minute trip. the thing fell off again and it stalled. i ended up having to tape the connector onto its little thing. i have no idea what its called or what it does. so i took a pic. i hope someone can help. ive put hell of a lot more money into this truck than its worth.

http://i44.tinypic.com/1196pmh.jpg
http://i43.tinypic.com/2nbbnfa.jpg

 

[1998Explodasport]

Which plug are you talking about?

 

[SIK99EX]

this thing. its hard to see it cause its taped on