My truck has been down for a couple of years and am now down to the last couple of issues. The engine will not kick down to a normal Idle speed. If I start it without touching the throttle, it will start and run at around 1200-1500 RPM and then drop down to around 800 RPM when it warms up as it always has. No problem. The issue is that as soon as I throttle it up to move anywhere, it will rev up to 2000 RPM and won't kick down. I originally assumed that the issue was throttle cable or linkage related to it having sat for so long, but, all cables and linkages are free over the full range of motion and work as smoothly as they did when I parked it. Any suggestions?

 

Check the TPS signal output and the connector. I had green stuff growing in the connector leading to the TPS. Clean out the corrosion with contact cleaner then apply a little dielectric grease.

The TPS may be compromised as well, but I do not suggest blindly tossing on an inferior aftermarket version. Check yours first after verifying the connector is not gunked up.