97 Ford Ranger

[quote:7d50140893="peter framton"]No codes. 1st half of throttle responds correctly, 2nd half feels as if engine is governed, tach shows no sign of slippage. feels as if pulling a load, with empty box. RPM seem low when placed into next higher gear. enging runs smooth at idle/ through out range.
thinking one of the sensors that feed the PCM, which in turn supplies timing.
have changed; fuel & air filters, plugs, wires, coils, running injector cleaner-2nd tank
any idea's welcome, thx.
2.3L, x-cab, 2wh-dr, 5-sp/manual, apx.120k[/quote:7d50140893]

Have you checked the brakes is they are dragging
With no load on engine the PCM limit’s the rpm to prevent physical and internal engine damage

I had the same problem with my 1996 Ranger. Was told to disconnect the battery for 5-minutes. This apparently will reset the electronic control unit (ECU). Make sure that any additional batteries are also disconnected. After reconnection it will take the ECU about 500 km (300 miles) to re-learn your driving habits. This worked for me. I had bought my Ranger used. Hope this helps you.