I have a 1.6 1997 skoda felicia. It idles rough and rpms drop when coming to a stop and pressing the clutch. I want to try cleaning throttle body, but i want to know if I'll have to reset throttle body afterwards? Or does it re-learn by itself? I don't have a vag com scanner.

3 hours ago, matej2212 said:

i want to know if I'll have to reset throttle body afterwards

Yes, you have to reset it via VAG-COM scanner.

3 hours ago, matej2212 said:

It idles rough and rpms drop when coming to a stop and pressing the clutch.

That is a well known issue. Skoda recommends first cleaning the pressure & temperature sensor for intake air. There are oily deposits and dirt on it.

Only if cleaning it doesn't smooth the idle, clean the throttle body.

Can you help me with locating this two sensors? And which cleaner do i use? Is intake cleaner ok?

You should also check the connectors of the MAP sensor.

47 minutes ago, matej2212 said:

Is intake cleaner ok?

Yes.

 

I cleaned the sensor with mass air flow sensor cleaner and it helped. Thanks a lot!

It's me again. The car idled fine for a couple of rides and it worked perfect, but now it idles poor again (the rpms go up and down). Is it possible that the sensor got dirty that quickly?

4 hours ago, matej2212 said:

now it idles poor again (the rpms go up and down)

I understand we are talking about a different issue. Now the idle is rough or hunting. Before that the engine stalled when decelerating and pressing the clutch pedal.

So it is not the MAP/IAT sensor that got dirty again. Normally it takes tens of thousands of kilometers to get dirty.

Now we are talking about the throttle body that needs cleaning/resetting OR the TPS (throttle position sensor) is worn out OR there is a vacuum leak in the intake manifold area.

 

Note: Make sure the throttle cable is not too tight before anything else.

Too tight meaning what? Does it have to have a little bit of freeplay in gas pedal?

A very small freeplay should allow the throttle plate to rest to its idle position.

Take this check as a prerequisite before going into deeper diagnose. It would be a waste of time/money to find out in the end that it was a tight cable all the time.

It has some freeplay, so that should be ok. It has had the battery replaced, is it possible that that is the reason why the computer "forgot" the idle?

Yes, it is possible. Give it a hundred kilometers of driving to see if things get better.

Probably won't help, I've done more than 700km since the battery change. Should I try reseting the ecu by disconnecting the battery and leaving it unplugged for 30min?

Then you will need

On 03/06/2019 at 00:58, RicardoM said:

Now we are talking about the throttle body that needs cleaning/resetting OR the TPS (throttle position sensor) is worn out OR there is a vacuum leak in the intake manifold area.

 

Okay, I got a chinese VAGCOM cable, hopefully it will work. What's the group number for throttle body adaptation?

Launch VAG Com. Selection of control unit. Ignition ON. 01 - Engine. Read error codes - 02. It is mandatory to do this before resetting the TB. Continue to Basic Settings - 04. In the Group box, type 098, press Start. The setting itself takes less than 5 seconds, experts recommend to wait 20 seconds. After 20 seconds, press Done, return, Exit communication, back - 06 and switch off the ignition. Experts recommend to wait 30 seconds. Then we can start the engine.

yeah, it says "this function requires vag-com to be registered and activated". I guess chinese didn't put the "correct" software on the cd that came with the cable

37 minutes ago, matej2212 said:

yeah, it says "this function requires vag-com to be registered and activated". I guess chinese didn't put the "correct" software on the cd that came with the cable

 

I don’t know, what’s the world coming to when cheap knock off copies won’t do what you want?

1 hour ago, matej2212 said:

yeah, it says "this function requires vag-com to be registered and activated". I guess chinese didn't put the "correct" software on the cd that came with the cable

I doubt it. Read everything carefully.

What should i read carefully? The instructions just say to install software from cd. I can read error codes (there aren't any), but when i try to go in 04-basic settings it says "this function requires vag-com to be registered and activated"

5 minutes ago, matej2212 said:

"this function requires vag-com to be registered and activated"

 

Not surprising really. 

Hi, it's me again. I still haven't figured what the problem is, but I have discovered that the engine stalls only when I come to a stop with low rpms and then press the clutch. If I go cca. 30kmh in second and then press the clutch it idles fine and doesn't stall, but if i go cca 20kmh and then press the clutch it stalls or idles rough. I have also discovered that if it idles rough and I press the gas pedal so the rpms rise it ussually idles normal again. Does that help with identifying what the exact problem is? Thanks again.

Replace the pressure & temperature sensor for intake air.

Ok, will try that. Thanks.

On 22/10/2019 at 17:45, matej2212 said:

Ok, will try that. Thanks.

 

How did it go?