2001 Diamante engine light on, car starts and idles just fine however, i cannot rev the engine. There is absolutely no throttle response at all, only idles. Changed the distrbutor cap and rotor, but no improvement. Please advise.

try using the scan tool to reset the ECM program
code p 2104 refers to throttle actuator control(TAC) system---forced idle mode ===causes ---wiring--TAC motor ---APP ensor--ECM
code p 2112 refers to throttle control actuatorTAC system---actuator stuck closed ===causes ---throttle body, throttle valve tight/ sticking
or TAC system--circuit malfunction===causes wiring short to positive ---short to ground ---throttle position sensor--- ECM

does the engine stay idling with no response to throttle movement? or does the engine cut-out when the throttle is pushed?

i'd suggest getting the cylinder compressions checked , black smoke indicates burning oil so could be piston rings , also that would explain lack of throttle response and low revs

gear speed sensor fail gear box is not reciving engine speed.

If the idle speed is above 2000 RPM then drops down to normal, the common cause is a faulty idle air control valve or a dirty throttle body.

If it was a fuel shortage the engine would rev but to limited speed. This is a lack of air to throttle body. Check for clogged air filter and all the piping and the throttle body.

Hi,

This definitely sounds like an Emission Control issue....

You should have your diagnostic codes extracted from you PCM - this will identify which circuit is causing this condition.

Cheers,

there will be a screw buy the throttle cable in the engine bay, i ask why do you want to up the idle revs if it runs fine at them revs

Sounds like you have faulty throttle position sensor (TPS) or TPS connection. Normally when you hit the gas the throttle plate jams open and the position change is immediately sent to the ECU which responds by extending the injection cycle to put much more fuel into the cylinders to accelerate the engine. If the TPS does not send this immediate information, the ECU relies on the mass air flow and intake air temperature sensors or Manifold absolute pressure sensors to detect and send signals. These are much slower to respond to throttle changes and so there is a time lag. If it is the TPS then a quick check is to see if you can catch the ECU out. Step on the gas very quickly when the car is idling. If the car stumbles or stalls it is because there was no response by the ECU to the sudden change in throttle and the engine was forced to run lean. The converse of this situation is that the engine often takes its time to return to idle after being at high revs.

You need to replace your IAC (idle air control valve). The IAC, like it sounds, control the idle of your car. When they go bad they will cause the low idle and stalling. The IAC is located on the throttle body and is usually held on with a couple of screws. It is an easy relatively cheap fix that you can take care of by yourself. Let me know if you have any more questions. Thanks for rating my response and for using FixYa!