I bought a 2009 Focus after the lift 1.8 duratec 125 hp manual. I've been observing strange rpm behavior for some time. As I move in a traffic jam and the engine is warm.
I let go of the clutch and drive up.
I hit the clutch.
RPM drops to ~ 750 rpm then the pointer lurches below even 500 rpm (It looks like the engine is about to shut down) and then jumps to ~ 800 rpm and stabilizes at 750 rpm.
The shorter the distance, the greater the turbulence. Everything stabilizes after leaving the traffic jam. If i pull off clutch pedal sensor the problems disappear. I replaced the sensor like this but it did not work. On a hot engine, I sometimes manage to get these symptoms when I hit 1 and release the clutch on the handbrake. There are no problems at idle, even after adding gas. There are no errors on the ECU. On the preview, I can see that when it is a turbulence, TPS closes to 12.9%.I don't know what else could be the problem. The TPS bundle is in a plastic hose.