new clutch pedal
 

I just picked up my 8 from dealer. They replaced my clutch pedal which had let go.


On my way home I noticed that while at a stop light when I engage the clutch and put the car in gear, my rpms automatically start to bounce between 1000 and 1500. I tried this a few times and every time while the car was stopped and I engaged the clutch and put it in gear the rpms began to bounce between 1000 and 1500. Does this seem normal? Any ideas on what could be the problem??

Does it also do it if you do not engage the clutch but have the transmissio in neutral?

My guess is that they either didn't connect the clutch position switch, knocked the sensor out of alignment, or didn't reset the plunger. This is the upper switch on the assembly that gets pushed in when your foot is off the clutch.

My rpms are normal (around 800) when in neutral. It only happens when I engage clutch and put in gear. If I only engage clutch nothing happens, just like in neutral.

Yup, 'd say that confirms it. Basically the ECU has 2 different switches to detect if your transmission is effectively in neutral so it can switch to a different map. One is the neutral switch in the transmission (which sounds like it's working fine), the other is the upper switch on the clutch pedal. If either one is malfunctioning, or there is any problem with the wiring in the circuit, then when you are in neutral (or clutch pedal to the floor), the revs will hunt between two specific RPMs as the ECU can't figure out what to do, since it thinks that you are in gear.


Get down there and take a look. Most likely the electrical connector isn't secured to the switch, though it could be that the switch is out of alignment or not seated properly. A few other possible causes, but those are the most likely. Simple fix.

Good call! That's exactly what it was, the switch wasn't seated properly. Mazda tech must have knocked it out of place when replacing the pedal. I put it in place and everything works fine now.
Thanks

Now it seems the ecu switch on the pedal was damaged. Mazda ordered a new one to replace it for me. Could a damaged switch cause my car to hesitate a bit when I get on the throttle? Seems to have lost some power since the last visit to Mazda. It even seems to sound a bit different.