I had to buy a new computer for it it cost 230 witch i got half back from the company I went to auto zone had it installed in mexi for 50 buck moor or less
Run a compression test to verify the condition of the engine.
Acceleration Cable broken broken, you dump!
Adjust the idle screw.
check for a vaccum leak start the engine and spray some starting fluid around the gaskets and fittings on the intake manifold if the engine speeds up there is a leak
because the rangers come with mechanical cooling fans so when the engine is cold it idles faster so the fan will run faster as the engine warms up the idle speed slows.
zyou tps might be bad
On my Chevy truck it idles high when its low on antifreeze but if its not that more than likely its usually a vacuum line loose or cracked. good luck.
Throttle linkage could be in a bind or TPS is defective. (throttle Position sensor)
why does my 4.75 BRIGGS & STRATTON lawnmower engine idles high and low when cutting my grass
If the engine idles and revs up okay in neutral, it is likely the torque converter clutch lock up solenoid.
Need a little more info. What Model and year of the vehicle?
Needs a Tune up