I recently bought 99 93 Convertible. Have been making oil changes every 3-4K miles with synthetic oil. Have noticed a tapping noise when inside the car. Can't hear it with the hood open very easily. The noise doesn't stop when its been warmed up. It has many miles 140K and know it needs work, but LOVE it anyway!! The turbo is starting to whistle as well. Can anyone help with some suggestions? I know these probably aren't easy fixes.