Rough idle at times and feels like it's missing at certain speeds

[nc87k5]

My 87 idles rough and at 25-35 mph, it feels like it has a miss but the plugs, cables, rotor button, and cap have been replaced. If I let my truck idle for too long, say after driving around town, it shows code 24, which is the vehicle speed sensor fault. Could this be the problem?

 

[dyeager535]

It COULD be. Since the code is indicating a problem, focus on resolving that first.

This link SHOULD work for the fuel and emissions manual, which should guide you in figuring out the code 24 problem. http://www.mediafire.com/download/i...Fuel_and_Emissions_Including_Driveability.pdf
If it doesn't work, you can find it in the link in my sig.

VSS in an '87 is very basic, so should be pretty easy to diagnose.