Low/poor idle engine ticking over revs in idle very low,rev counter will shoot up and down revs up on its own. Changed air flow meter no change

Could be the Throttle Position Sensor. Just changed mine and it now idles properly. Mine would occasionally surge when at idle. Mine would also rev around 1500 to 1800 at startup and take a very long time coming down to normal idle. Changing the TPS has solved all my idle problems.

This is called hunting. Can be caused by a bad mass air flow sensor. Could also be a sticking idle air control valve.

replace the viscous fan hub or check the electric fan operation as you do not have a forced air flow at idle. When the engine is working hard at low revs (pulling up hill) there is insufficient road air flow and at idle at lights there is no road air flow

i've got trafic 100dci 2001 year-had poor exceleration upto 2000 revs then turbo cut in,also at speed-mainly uphill the power would start to pulse(like small jerks forward)until it ran out of steam-80ish,changed egr valve-didn't fix it! then tested air flow meter and found figures incorrect,so replaced,also tested the tubo rod(down the back of the engine -visible with air filter housing removed)this was very stiff,so used wd40 to clean then spray oil to lube and worked the rod backward and forward until it moved freely.put all back together and that was it-back to normal-hooray!! have to point out that the van will not rev past 3700 revs when it is loaded-it has a load sensor,unloaded or partly loaded it will rev to I think about 4100 revs(don't quote me on that though) do hope this will help whoever and God bless

VWs are not well known to have idle issues however, a bad or stuck Idle Air Control valve, or a bad Mass Air Flow meter can cause this issue.

Have the TPS (Throttle Position Switch) checked with a milli-volt meter, it seems like it is not working properly or is dead. if it is not working it won't send a signal to the ECM (Computer) to let it know how much the accelerator pedal is being depressed so it cannot know how much give fuel and air to give the engine. Also have the MAF (Mass Air Flow) sensor checked.

you need to clean or replace your idle air control valve(IAC). The IAC allows your engine to idle smoothly by opening and closing a valve that allows air flow to the engine that is monitored by the computer. The IAC get dirty causing it to stick and move slower than it should which causes the up and down idle

Sounds like your "speed sensor" is failing. When it fails it will cause irregular shift patterns and engine idle speeds.

The battery could be slightly weak, making the computer go on the fritz, try a fresh battery!!!! The rev counters bounce often with a weak battery.

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it's your idle air valve located on the backside of your intake round with two large lines going to it make sure you check junkyards first for one because you'll faint when you hear the price at the parts counter.