sl1 missing when idling
 

When driving my sl1 it would run great but when I came to a hill when I pressed on the gas to maintain speed it would sputter or miss a couple of times and then would run fine again. I changed the spark plugs and the problem was solved. Now though when I come to a stop at idle it will sputter every 5 or 6 seconds and drop a couple hundred rpm like it is going to die but then catch and go back to normal. Any suggestions?

Might be fine for a full tune up

NGK plugs only, dealer bought
Plug wires
Clean throttle body in and out
Air filter
ETCS and connector, dealer bought
Be sure no oil is getting into plug wells, replace cam cover if it is
Be sure no white crude is on the coil pack towers, replace if there is

RjION is correct. It sounds like defective plug wires. Look at the plug wires while the engine is running, at night, while increasing and decreasing the rpms. Or you can test them with an ohmmeter.