Pat,
Sorry I haven't replied sooner. I just got too much going on. I want to send these two photos to show you the screw I was talking about. This screw does change the idle when I mess with it. I had to turn it some, or thought I needed to so I could get the timing set and I forgot how much I turned it. I was thinking there was a factory setting for it. If it is set to much one way or the other would it make the engine start sputtering after it's warmed up ? It starts fine and sounds like it's running good until the engine gets warmed up then when up around 1200 to 1400 rpms the engine will start acting up. It's the straight slot screw. Hope this helps some.

 

Yep, that's the cover, or cap screw. It covers and protects the Idle Adjust screw, which is a smaller screw under the straight slot you're indicating. If it adjusts the idle at all, it's because the o-ring on the actual IAS is crumbling, and it's varying the amount of air leaking in. Try taking that cover screw off, and check the o-ring on the smaller screw under it. Most likely it need's replacement.

Hope this some help..
Pat☺

 

Pat, thank you for that info. Now the actual setting screw under the cap screw, is there a factory setting for that screw ? I thought I had read on this forum to screw it all the way in then back it out 1 1/4 to 1 1/2 turns but not sure if I'm correct about this. And would it cause the sputtering problem I'm having when the engine warms up. It sounds almost like with the old carburetors flooding the engine when not adjusted right. First time I've ever had this problem. Pretty sure I can get another screw from Rock Auto.

 

Unless it's damaged, you don't need to replace the entire Idle Adjust Screw Chances are, the o-ring is damaged/disintegrating. The o-rings are available at most auto parts/hardware stores. It could be that the Throttle Body is getting sufficient air from the Idle Adjust valve, which should be closed once the vehicle is at full operating temp. Like I said, someplace I'm sure, screw the IAS all the way down until it touches, counting the turns. Then you can unscrew it all the way out, and replace the o-ring. Once you have that done, and again, a bit of silicone grease or Vaseline spread on the o-ring is highly beneficial.
Once this is done, put the IAS back in, screwing it all the way in until it touches bottom, the unscrew it until it matches the count you got before. This is a good starting point. Before you do this, make certain the air passages under the IAS are totally free of bits of o-ring.
Let the truck warm up to operating temp, then you can adjust the IAS to get the idle to about 8-900 RPM. Put the cap screw back on, and voila! All is now well. Simple task, easy to do, out in the open, easy access.

Good luck to you!
Pat☺

 

Thanks again Pat for your help. I'll do as you instructed as soon as this rainy weather breaks and let you know happens.
Also, thank you for your service to our country, your retired daughter and one that is in the Navy.
Greg