Serious Engine Rev Issue, ... changed cable, convinced it's vacuum related?? Options

[vesnyder]

Had this issue before my recent engine pull, but it is back. When coming to a stop and push clutch in the engine just redlines? When it first happened I assume it was the throttle cable sticking, but after replacing it has to be something else? What else could it be? It is fairly random - does not happen every time I stop. The last few times I just shut it down and start it right back up, and away I go! One of these time I am going to do some damage to the motor! Any ideas on what it might be? Something part of the vacuum system or throttle body that could be sticking? Not a safe issue to have! HELP

[Demick]

As others have said, it is very likely the throttle cable (even if you replaced it) because unless specific precautions are taken, it is natural to wrap the throttle cable around the clutch cable.

However, if this is not the case, it can be your deceleration valve. When they go bad, it usually causes very high idle like you describe. To test, just disconnect all lines going to the decel valve and plug them all (plug the disconnected hoses, not the decel valve ports). If the problem goes away, then the decel valve is your problem. Either replace it, or many people just remove it alltogether and leave all of the lines that went to it plugged. It's mostly an emissions device.

Demick