can someone please tell me the best stock type plugs to run in a 1986 190e SOHC? maybe a particular brand of copper core plugs that were OE, or what the parts stores are sellin now to replace said? this car has those iridium type four prong flat electrode type in it now, and i've read the engines don't run well with them installed, or am i backtracking here? before i do any more adjusting to the idle, etc., i'd like to try this simple fix first. the cap, rotor, and wires appear to be very recent, as well as these plugs,(minus the high carbon buildup) but somethin tells me they are the wrong heat range, and are probably gapped incorrectly as well. maybe someone has had a similar problem, and can shed some light on this problem for me...i have been shopping around and would like to replace them with maybe something that will help it run better. runs great while you're goin down the road, but idles like crap, and someone on here says i should try this first which i'm trying to resolve! thx to alll for any advice or suggestions on this problem! i also would like to know if i should go with a colder heat range on the plugs as i'm still learning about this car...