Rough Running and Idle

1997 F-150, 4.2L, 120,000+. After truck warms up, idle still seems high and truck runs rough at all speeds and idle. Feels rough during acceleration.
Sometimes when shifting from 1st to 2nd and from 2nd to 3rd, engine surges for 2-3 seconds after backing off accelerator. When stopped at intersection, sometimes engine will idle high and sometimes will drop down to near normal. I've replaced plugs and will replace wires today. O2 sensors were replaced six months ago. Pulled off EGR valve and found no blockage. Pulled IAC and it looks OK, saw no blockage. After replacing plug wires, I'll check the spark at the coil. The TPS is attached with two Phillips head screws that are EXTREMELY tight and I could not get them off to check the sensor. How can I get the TPS off without damaging it, or should I just try to drill the screws out and replace them and the TPS? Can I spray throttle cleaner in the IAC and brush it out with a small toothbrush? It doesn't seem that dirty, but maybe there's something in there that I can't see. Anything else I should check/replace?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It sounds like a vacuum leak to me. Have you checked the hoses? Are you sure the intake system has no leaks?
CJB
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I also thought I had a vacuum leak. I had the intake checked and no leaks were found and I checked all the hoses and could not find any leaks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.