1989 Silverado Idleing Problem

[Camaro_nut2001]

Hello, I have a 1989 Silverado 1/2 ton 4X4 with a 305, automatic. It has the throttle body. My problem is the truck idles way to high when warm, really all the time but is faster when warm. I have replaced the TCS, IAC & the TPS. Nothing has helped. I have cleaned the throttle body plates & shaft & checked for vacuum leaks everywhere I can think of including the intake. Also, the trans shifts too late & jerks from 1st to 2nd & it won't adjust with the cable. I have it almost all the way in where it should shift real fast & soft but it doesn't. Right now I have the TPS & the TCS unplugged & it idles great just a little hard to start. I haven't driven it to see if the lower idleing has affected the trans shifting as I want it right & all the sensors plugged up before I drive it again. It is not throwing any codes with everything plugged up. I traded for this truck about a month ago & it was idleing a little fast but nothing like it is now. I'm stumped on the trans shifting also. I have a '96 Suburban & it runs, shifts etc..... great with 279,000 on it. If ya'll could give me some suggestions it would be soo appreciated. Thank you.