On my 96 VW Jetta, every so often, more so when it is a cold engine, maybe a few minutes into it, the idle will fluctuate from about 600 to about 1200 rpm, and if you let it be for about 5 seconds, the idle will go up to about 1200 and then about 10 seconds later it will return to normal, or if I quickly floor board it and let back off, it will clear it all out.

Any thoughts, ideas or suggestions on what it could be?

Idle control valve sticking? I have the VR6 and it was doing the same thing. I ended up replacing all the sensors in the coolant housing, the TPS and cleaning out the Idle valve. 90% better. VWVortex.com is a great resource.

What sensors would be in the housing, coolant temp sensor?

About where is the idle control valve located?

http://www.ebay.com/itm/VW-Idle-Air-Contro...2e6&vxp=mtr

You replaced the TPS as well?

http://www.ebay.com/itm/1993-2004-Volkswag...3d1&vxp=mtr

The TPS shouldn't be an issue for you, but mine was cutting out at 2k rpm and would jump up in rpm when driving/and or cut out. Here's a photo of the valve mounted from the Vortex site.
http://forums.vwvortex.com/showthread.php?...ight=idle+valve

Brake cleaner is alittle too agressive. Maybe use a throttle body cleaner to spray inside it and wipe down. These motors don't like air leaks. So check all your lines, etc.

Regarding the sensors, it's my understanding from the threads on Vortex, that the blue coolant one is typically the culprit. There is a yellow temp sender, a blue coolant sender, and one for the AC. But, If your going to replace any, I would do all 3 if cleaning the valve doesn't help. The temp sender and fan switch on the radiator should be matched to your thermostat as well. Also chase down vaccum leaks. That's the cheapest way to go before you start tossing parts on it. Do you have any engine code faults? Any shop should be able to read them if your car is OB2, which I think it would be. Hope that helps. I'll try to locate some of the threads I used when trouble shooting mine.

I don't see anything that resembles the picture of the idle control valve, unless it is the small shiny canister type thing on the left front of the engine, but that doesn't have any electrical wires going to it, or is it that black saucer shaped thing to the back of that??

I could have my mechanic check to see if there are any codes, but nothing on the dash.

My electrician told me the best way to check for leaks is to spray carb cleaner on the lines while it is running to see if it speeds up to determine where the leak is.



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I'm not familair with the 2.0s at all. It seems that the shinny canister would be it on your car though. Wouldn't hurt to try. Cpt Krusty on this board might be able to help you, or post on Vortex. I'm sure there are plenty of threads on it over there. Sorry I couldn't help more.

With the Eurovan, a 1993' its the old digifant fuel injection.
It's all controlled by the coolant sensors, there are three.

Replace all off them, the coolant kills them off.

Check the intake system for oil from the breather. Clean the throttle body and the intake hose. K&N filters are well known for contaminating the MAF sensor; clean it ONLY with MAF cleaner. That "MAY" work, if not, replace it. That "shiny" can is the fuel pressure regulator. More later, if you need it.

The Cap'n

No wonder I couldn't find the IACV. There isn't one on this year, according to this article.

http://www.justanswer.com/vw-volkswagen/4j...ve-located.html

This last summer I cleaned the MAF with the special cleaner and up into the throttle body, but no better. My mechanic today told me to take it off completely and clean in behind it as well and replace with a new gasket. I presume it is called a throttle body gasket?