My early 99 has had a rough idle / miss for alittle while now and I have no codes and no ses light. This is not a "wandering idle" it feels like I have a miss fire as I can feel it all the way through the rpm's. it is especially bad when it shifts to overdrive and pulling low rpm's. I was thinking UVCH and went to check it this morning and it seems my multi-meter has gone bad because I can not get any reading on ohms. Well then checking other simple things I pulled the connector off of the ICP sensor and found engine oil inside. Is this a problem??? Also I thought that if you had a bad sensor and a rough idle if you pulled the connector it was supposed to clear up????? The truck seemed to rev for a quick second then went right back to rough idle. Help please.

 

Sounds like your ICP is on it's way out, but if it was the problem the motor would have smoothed out as it transitioned to the default fuel pressure table. UVHC is still a good thing to check. Clean fuel filter, good oil?

 

https://www.ford-trucks.com/forums/7...op-lights.html I just went through what you are experiencing. My truck even liked to stall. The attached thread tells the story of my truck. My problem was the ICP. Hope it helps.
John