I don't know if anyone else has experienced this issue before, but I have noticed that when I start the car, then put it in drive and start rolling, the car vibrates violently for about a second as if it's about to stall, then clears up. I'd say that this happens about 10 - 15% of the time. The engine doesn't throw any codes and the scan results show nothing -- could it be a coil pack starting to go bad? Any other thoughts?

 

How old are your spark plugs and what kind do you use?

 

The previous owner replaced the spark plugs at 40K at the dealership. I have a little more than 20K driven on the plugs.

 

Don't know. But what you are describing is misfiring. On a cold engine one would suspect plugs are not firing for some reason. I would want to pull the plugs and look at them, check the gap. The gap is supposed to be .032 and when I checked mine they were set at .025 - .028, which will cause cold firing. Looking at them will tell you if they are fouled from oil or moisture too. Coil packs are problematic but I would think you would have hot problems instead of cold problems.

 

OK, I will look into that. But gapping aside, is it about the right time to be changing the spark plugs?

 

There are a lot of varying opinions on which plugs to use. Some believe copperare best and change them at 5k. Platinum are factory plugs and can last 40k. I am using platinum and won't change them until I see them wear. But it really depends on who you talk to and if they have performance upgrades. Perhaps others will add some info here.