Rep Power: 0

So I was working on my parents' 2003 Civic and I noticed that there was a noticeable gap where the gas pedal was totally unresponsive. I looked under the hood for the throttle body, and found out that there was a gap between the throttle pulley and the actual mechanism. The throttle mechanism was unable to return any further, it seemed as if a screw was physically preventing the lever from going all the way back.

I plugged in an OBDII scanner and saw that the throttle was stuck at 9.4% even when nothing was touching the gas pedal. Also, the throttle seemed to max out at 86.3% when fully depressed. (see pictures)

Diagnosis:
-Throttle cable was not loose
-Cable had a proper amount of play
-Turning the adjuster screw did not help
-None of the moving parts were sticky whatsoever

I wasn't able to fix the problem, and it is pretty concerning that the idle is stuck at 1300rpm. There were also very few search results that described this situation. Any advice would be appreciated!

 
Rep Power: 519

Was there any fault codes?

Throttle % values are probably normal for using a generic scan device. If you could read TPS voltage it should be 0.49v at closed throttle.

If you backed off the locknut for the positive throttle stop and that screw moved, you may be in trouble. That screw sets the minimum position for the throttle blade....If it got backed off the blade will stick in the throttle housing (sticking gas pedal). If it moved inward to open the throttle, you'll have serious trouble getting it to idle right...after figuring out the original problem.

If I were to check using one of my scanners, I'd make sure the TPS reads 0.49v..




There must be a little slack in the throttle cable to allow the throttle blade to close all the way, and when someone pushes the pedal to the floor it should open the throttle blade all the way to its stop (nearly 90 degrees of movement).


Is the throttle closed? Remove the air filter lid and take a look.

Start it up, stick your fingers in the throttle body and plug the hole you can see in the side of the housing.....RPM should drop a whole bunch. Does it?


The IAC valve is likely just stuck open. With the engine running, tap on the IAC valve with a screwdriver handle a few times. If the idle changes AT ALL that is the problem.