I would appreciate it if someone could help me with this problem.

The car needs a little throttle to start up. Then it will idle roughly for about a minutte or two. Then the problem goes away. It only happens the first time of the day the car is started. It seems the longer it has been since starting last time the longer it runs roughly.
A shop changed the headgasket and the problem went away. Now, a couple of weeks later, the problem is back. When they changed the headgasket they said the car was running on three cylinders just after starting.
The sparkplugs has also been changed.

Anyone know what could be causing this behavior?

 

Are you throwing any codes ?

 

No.

 

It sounds like your engine don't know how cold the engine is and its not supplying the right amount of fuel. What engine do you have and what year is your car ?

 

the engine is B18C5 (Euro Type-R)
year is 1998

 

have the same problem with my type r usdm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WCI &raquo;</TD></TR><TR><TD CLASS="quote">have the same problem with my type r usdm</TD></TR></TABLE>

Is it getting worse?
Have you tried to fix it?

 

I've got the same problem with my b18b1...things i've been told...
1. make sure the coolant is bled good, if you have bubbles it can cause it to idle funny
2. IAC valve this can also cause a car to idle funny
3. Fuel Filter, this is one thing that i was just told and getting ready to do (i'll let you know how it goes)
I've bled and bled the coolant, and i've cleaned my iac valve...so now its on to the fuel filter...if anyone else has this problem let us know how you fixed it.

 

I talked to the Honda dealer today, and they said it might have water in a cylinder and that was causing the headgasket to fail. I asked if water would'nt bend valves or do worse to the engine, but he said it might also give this behavior.
Does that sound right? To me it sounds strange that the engine could run fine, after a little while, with water in a cylinder, but then, I am no mechanic.

 

If the cylinder is FULL of water, that's hydro-lock. That'll break things, massive damage...

If there's a little water in there, enough to make the spark plug wet, or even just damp, that's what he's probably talking about. But if it's coming from a leaky headgasket, it can't do anything but get worse if you ignore it.

 

Take off your IACV and clean it using Break/Carb cleaner and put it back on...

also take off the fast idle valve plate (underneath the TB), and tigthen the white diaphram that is inside there.