I have a 99 S250TXRX that is running well (5600 WOT) but seems to smoke and run rough at idle/low speeds. I've done all but (2) recommended items since purchasing used last year <250 hours>. Still need to clean the o2 sensor, that I'm sure needs it. The second item/check was to validate resistance on the Spark Plugs Caps. Yesterday I ended up running an ohm check not just from the cap alone, but from the Spark Plug cap to the disconnected lead from the Coil. (5) of them <#2-#6> were at exactly 9 ohms. The #1 Plug/coil failed to get ANY resistance.....I tried for 10 minutes so I'm 100% positive with result? I checked the Spark plug and it is NOT fouled ....+ I wouldn't think so hitting 5600 RPM.
QUESTION - Does anyone know if 9 ohm across Cap/Coil is correct? AND - most importantly, how do I explain NO resistance across Cap #1 ....and still running great at top end? One local dealer mentioned a potentially Bad Ground on that coil? Thx for input here.
QUESTION - Does anyone know if 9 ohm across Cap/Coil is correct? AND - most importantly, how do I explain NO resistance across Cap #1 ....and still running great at top end? One local dealer mentioned a potentially Bad Ground on that coil? Thx for input here.