Hi,

please help me to figure this out. I own 99 Accord EXV6 sedan 60Kmi on it, no engine mods.
I started noticing that while idling my RPM _sometimes_ drops to about 300,and comes back in 2-3 sec. The same now _always_ happens when I switch gears from P to D or especialy from D to Reverse.
A few days later my check engine light came on.Tryed self-diagnostics counting number of flashes - it did not flash
Went to a shop, they read the code P1491 = EGR valve insufficient opening. They removed the valve, broke the gasket, could not find a replacement, ended up blocking intake and exhaust openings with a piece of sheet alluminum and simply bolted the valve back on top.
Is this OK? How long can I drive like this??

After re-setting the code the light came on again 10mi later.
After all this I still have the rpm drops.

The main question is can this be some other problem with idling?
As far as I understand, EGR valve only opens up at cert. temp and high RPM, so why do I have rough idling drops when EGR is blocked? I dont want to pay around $150 for new EGR just to learn that there is something else is wrong with emission system.

Thanks