Quote:
Originally Posted by Rversteeg
The only function of the TPS is to tell the ECU when the throttle is closed. Together with the current vehicle speed the ECU decides when to stop injecting (during coasting) or when to re-adjust the idle speed. For obvious reasons the ECU should not re-adjust the idle engine speed if a higher speed is caused by pressing the throttle pedal (TPS open) and/or if caused by the vehicle speed driving the engine (vehicle speed > 0).
A correctly set TPS will open just when the throttle cable starts to open the throttle plate. If this is set too critical, the ECU will not adjust the idle speed and maintain the initial idle speed setting of when the (cold) engine was started.
Note it will also not re-adjust when the vehicle has been constantly moving since its first startup. Re-adjusting takes one or two seconds of standstill with a warmed up engine.
The idle speed may be higher than normal, but it should not be vibrating or being irregular (or is the AC switching on/off?). Is this only in wet / damp conditions? That would be pointing more towards bad HT leads / distributor cap.
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So, the vibration and fluctuation of idle speed might not be related to the high idle when wet. In fact this high idle thing is only when it's rainy. The "rythmic misfire"/idle fluctuation happens all the time. Also the car shakes at 1500-1700 specifically too.
It has nothing to do with the AC. Also Ht leads are new, plugs well gapped, etc. IAC cleaned but not tested. MAF tested and it gave abnormal readings. At the time I asked you your opinion about the values, because you were helping me figure it out, but you must have missed my reply.
This wet thing does sound a lot like rotor/cap cause I've had similar issues on an Opel Corsa years ago. But the cap and the rotor do look in great condition and I cleaned them and it made no difference.
Here is video of the needle at idle, like it is normally, when the air is dry/normal. Do you think it's is a misfire?
[YOUTUBE]
https://www.youtube.com/watch?v=bTt45bXXayA[/YOUTUBE]
If you see the video, you can see and hear the car shake when the needle drops.