Idle and digital dash

[beechwoodrick]

Have a garage kept 90 C4. Took it on a trip and parked in steady rain for 3 days. Went to go home and no digital portion of dash and would not idle below almost 2K. Drove home anyway....seemed to dry out after couple of hundred miles and dash re-lit and engine idle smoothed out. After storage for winter...no idle below abut 1200 rpm and speed reads 0 and no A/C. Drove it a bit...starts and runs fine and strong, but does not come back. Gas trip meter and all regular gauges work. Suggestions?

 

[muskiemike]

I have a '84 that had high idle, similar to yours, then at trigged an check engine, which as code 21 = throttle position sensor - replaced the TBS, and the car now idles like it should, (700 RPM) and runs SMOOTHLY.

The TBS may be your problem as well.