So my truck has been running just fine for years then several months ago the idle starting staying high sometimes. Now all this week it's been at 1400rpm no matter what. Could it be the IAC? The computer? Can a tuner be used to reprogram the idle? The motor still runs great.
Thanks

 

I would suspect the IAC. It could also be a massive vacuum leak too. You might want to check your vacuum lines. Those little plastic lines can get brittle and break over time.

 

Thanks Windsor,

Someone suggested to reset the computer first which also resets the idle so I pulled the battery cables and attached the 2 cables together (no battery) to completely reset the PCM. The battery posts needed cleaning anyway so when I finished that I reconnected the cables and "presto" the idle has been back to normal on 5 short trips around town.

It just did not seem like a vacuum leak because the motor still ran smooth but with a very high idle. Time will tell tho.