The exhaust tubing is kinked.

Repair or replace the damaged tubing.

The exhaust particulate service filter is restricted.

1. Remove the exhaust particulate service filter.
2. Inspect the exhaust particulate service filter for a restriction.
3. Replace the exhaust particulate service filter if the condition of it is doubtful. Refer to Exhaust Particulate Service Filter Replacement .

The inner layer of the double layer pipe is separating.

Replace the pipe. Refer to Front Pipe Replacement or Intermediate Pipe Replacement .