My XH falcon is idling normal but when you tap te accelerator peddle it revs at 2000rpm for 5 seconds before slowly coming back to 1300 before dropping sharply to idle

That valve is going to have to be calibrated to 1100 RPM with the air on........You may be able to open a cover and adjust the pentle.. the Hondas you lightly bottom them then back off about 1/16th of an inch turn.....

Try this. If tps is positioned correctly and idle is correct.

You can recalibrate the throttle yourself to eliminate flat spots or pauses in its response curve.

This should work on most Fly by wire cars, they work on chevy and dodge for a fact

1-ignition to RUN but do not start
2-wait until all the dash warning lights go out (engine light should be the only one to remain on)
3-slowly depress the gas peddle to the floor (take at least 15 seconds to gradually push it to the floor, do not waver as you push)
4-slowly release gas peddle to full up (again, take at least 15 seconds to gradually let it back up, do not waver as you let up)
5-ignition to off
6-DO NOT START IMMEDIATELY! Allow to sit for up to 10 mins+, then start and check for difference in response and linearity.

sounds like you speed sensor and your throttle poistion sensor

What engine does it have ? Could have come with 5 different ones . If it has the 1.6 L engine . has electronic throttle control.
The throttle actuator control (TAC) system is used to improve emissions, fuel economy, and driveability. The TAC system eliminates the mechanical link between the accelerator pedal and the throttle plate. The TAC system eliminates the need for a cruise control module and idle air control motor. The following is a list of TAC system components:
• The accelerator pedal assembly includes the following components:
- The accelerator pedal
- The accelerator pedal position (APP) sensor 1
- The APP sensor 2
• The throttle body assembly includes the following components:
- The throttle position (TP) sensor 1
- The TP sensor 2
- The throttle actuator motor
- The throttle plate
• The engine control module (ECM

Check engine light lit ?

Check for vacuum/intake leaks.

Do It Yourself Diagnosis and Repair

sensor problem,without the right equipment it will be cheaper to put it in the dealers

Sounds like your throttle is sticking, try looking under the hood for a cable that come out of the firewall. WD40

I have the same Jeep and same problem. The engine was running rough. The Jeep dealer fixed a vacum problem in the manifold and they then decarbonized and cleaned the fuel injectors. After these repairs the idle problem began, it would spike to 2000 rpm while sitting at idle, sometimes it would slowly come down, sometimes I would have to tap the accelerator. I took it back in and they then replaced the throttle motor and reprogrammed the PCM (Power Control Module?) Still same problem. Now they suspect a another vacuum leak and I am taking it back in on Tuesday, will let you know what happens, $ 1,300 so far.

you need to have the fuel pressure checked

the harder you drive your car the quicker you wear out parts and wearing out of parts causes decrease in performance.so technically yes it does eventually "kill" it.