engine once in a while loses rpm at idle
 

hi,
ive read a lot around here for all kind of info and i have to say very nice site, but heres what bothers me:
when car is on idle, it keeps perfectly fine at 800rpm but once in a while(lets say once in 20min) car loses rpm to ~400 for a piece of second and then goes back to normal.
ive read in other threads that EGR problems causes car to go terribly rough, but at load im going fine and most of time at idle too.
changed all filers, oil and timing belt. just got spark plugs recieved and going to install them tomorrow or so.
the question is what could cause the problem im having? also im getting bad mileage (~16mpg city)
another questin is what would happen if i disconect EGR system by removing vacum house from EGR valve (house #16) ? i have heard that other guys is doing it on other cars on porpose to not let exhaust gas back in engine and some are saying car goes stronger and mileages improve. im not getting a very good gas in my location, so maby its an option for me to remove EGR ?
for add info i just bought this car and dont have a clue what was going on with it befor i got it.

RE: engine once in a while loses rpm at idle
 

Once in 20 minutes is pretty far between events. It's even a little long to be sitting at idle anyway.

EGR shouldn't be active at idle. Possibly clean up the EGR system so it works correctly. But seems to me that your idle stumbling could be caused by a dozen other things besides EGR.

You said in your other thread you're in Latvia. Gas quality?? The purpose of EGR is to reduce the combustion temperature, and if your gas is questionable, higher combustion temperatures may not be a good idea.