I just replaced my oil trap and cleaned the pcv. While I had it all apart I figured I should clean the Throttle body as it looked pretty dirty. My car 2000 T6 looks like it has had the replacement ETM, the sticker is yellow. Put everything back together and the car barely idles now. It surges at idle until it almost dies. It's driveable with a noticeable lack of power but won't idle. I double checked everything pulled the whole thing apart again to make sure I hadn't missed something, put it back together, same problem. Could I have messed up the ETM by cleaning it? And how would I check it? No codes have shown themselves yet.

One odd thing, I checked the coils just to see and I did so with the charge air cooler tube not hooked up, when I covered the pipes from the turbos with my hands and applied a bit of backpressure the idle smoothed right out, as soon as I took my hands away it started surging again. Any ideas?

 

You have all ppipes hooked up?
Make sure you don't forget at the intercooler.
Also dumb question but is the throttle body plugged in?

 

I'm pretty sure all the pipes are hooked up. I originally forgot the one at the intercooler and also the small plastic pipe going to the pvc broke and I could hear it sucking air. I was so relieved when I found these 2 things but after I fixed them there was absolutely no difference with the surging. I will pull everything apart again today and look again.

Unless I have the vacuum hoses hooked up wrong somehow, but they're pretty hard to mix up.

Maybe I didn't make a good connection with the throttle body but it was plugged in.

Any chance the Boost Control Valve would make it surge? It threw a code P1238 but I figure it was just when I pulled the vacuum hose off the underside of the air intake or the one at the charge air cooler pipe.

This car is starting to give me a headache!

 

Something new. I started the car this morning and it ran nice and smooth, I thought great, it's worked itself out. Then it warmed up and started surging again, real rough idle. So it doesn't do it cold it only does it when its warm, why? If the rain stops I'll tear it all apart again, maybe a gasket is leaking. What about the MAP sensor or the IAT sensor, would those cause any problem like this?

 

It is possible but kind of rare.

I would double and tripple check everything.

 

Update: I took the manifold off again to check if I had missed something. Nothing obvious. I bolted it back up, same problem.

I pressurized the intake to check for leaks. Found one at the charge air cooler pipe, which I knew about. Leaks at the PTC on the intake tube. Tiny one at the bypass valve. And some bubbles coming from the ETM intercooler pipe at the ETM connection, but very hard to see. None of them looked serious enough to cause this idle problem. Pulled it all apart, bought new Volvo intake gasket and ETM gasket. Cleaned IAT sensor, tested it. Bolted it back together. No idle problem. Took it for a drive, Missfire and no power. Gosh when will it end. Drove it around the block a few times missfire dissappeared everything back to normal...For Now! On to the CAT/Oxygen Sensors.

Everytime I take the car apart I feel like I'm going to wreck something or a sensor is going to stop working. Its nerve-wracking frankly. I'm sure one of my coils is going to go any minute!

 

The coils commonly go bad.