I recently purchased a 93 ranger stick shift. It just had the clutch replaced. Every once in a while (maybe once a week) I will be cruising at 20-40 mph and I release the gas and the car will maintain its speed. As if the cruise control was on. The cruise control doesn’t work. I have tried to use it multiple times.
When I am stuck at 20-40mph, or whatever speed, I will push in the clutch, turn the cruise control on/off/on/off, even try pounding the gas with the clutch in, or saying ‘oh sh*t’; But nothing seems to disengage the throttle. It seems to stay at 1500rpm (hard to tell with loud muffler) until I turn the truck off and restart it and it runs fine. It seems to occur after I have been driving for a while or at higher speeds for a certain amount of time. After the truck is good and warmed up. Like after driving on the highway for 10 minutes.
Is this a cruise control issue? a throttle/gas issue? or some type of vacuum hose/pressure issue? Maybe my ranger caught the Toyota bug?
I would try cleaning or replacing the Idle Air Bypass Valve (AKA IAC). It sounds like it may be sticking open. Of course, there are other things that it could be instead.
I would pull the idle air control valve and clean it really well, and clean the throttle body - might as well just pull the throttle body since the IAC just mounts there anyway. You will want new gaskets or gasket material handy.
These things are just one possibility. I would do it b/c its cheap and easy and good maintenance either way. So even if it didn’t turn out to be the problem I wouldn’t be thinking of it as time wasted.
You should also check your throttle cable and linkages. If something there didn’t get routed correctly or is just binding from age this can happen intermittently.
Pull out the floor mat. Happened to me last fall in my 95. Make sure the cable is lubed, where it goes through the firewall, it might be binding up. It is a direct cable (on my 95 anyway)
If none of the above,
look into the throat of the throttle body where the round butterfly opens and closes. It can wear a groove and become hung up on that. Work it with your hand while looking at its path.
( I had an old Taurus that wore the edge of that butterfly resulting in a slight crescent of space which would therefore never completely close resulting in a constant high idle. It took a long time of multiple repair attempts till someone chanced to see the space. )