Last week the car began running rough and the check engine/TRAC lights came on. The same thing had happened in February and at that time I took it to a shop where they diagnosed/replaced a bad coil on #4 cyl ($250.00). This time, since I did not have a diagnostic tool, so I checked the coils the old fashioned way by disconnecting them while the engine was running to see if it made a change. On 2 of the cylinders there was no change, so even though I thought it unlikely 2 would be bad at the same time, I replaced them and the car ran fine for 2 days. Today the lights came on again and the car stumbled during acceleration. I borrowed a diagnostic tool and it reads 6 codes... 5 for faulty ignition on specific cylinders and 1 for general random misfire. Any ideas what could cause this? I don't think it's a bad batch of gas, but who knows? Thanks...