There are tree different things here:
One problem is water down to one of the sparks. Then the engine misfires
when revving and driving normaly. This happens as the engine gets warmer.
Mine was running on three cylinders when I had this. Fixed in a few minutes
by my dealer just removing that water.
One other thing is low performance the first 2-3 minutes after starting
a cold engine. It feels like you have 30bhp, but apart from that the engine
feels normal. After 1-2 minutes there is a little "click" and then the engine
is normal agein. I think this is explained why in this link (ECU). ECU limits
the power when the engine is cold. Chiptuning the car can get rid of this.
Sometimes on cold starts the engine has difficulty revving, but after a few
seconds of pumping on the accelerators the revs come back. The car will
still have a bit of a problem pulling away but a few secs later it will be
ok. After a couple of minutes things seem fine. No problems at all. This
mostly happens on hot days and if the car has been parked in the sun.
Then try turn off the engine when the problem occurs and start it up again.
If that helps, then this might be a problem with one of the following three things:
- Faulty O2 sensor (lambda sensor)
- Faulty water temperature sensor
- Faulty air mass meter (MAF) <- most likely & most expensive
This one can also be caused by the cables to the MAF gnawing against the
engine cover so bad that one or more of the cables snapped inside. Impossible
to see. Solved by cutting off 1 cm of the cable and attaching it again.
Be carefull with this!
It can also help to clean your MAF as it sometimes gets "dirty". Read more here.
Thanks to the guys on the forum here on this page for help with this, and
very big thanks to Vidar which helped me a lot on this!