Here are the mistakes identified in the sentences:

1. **Peter wished that he has gone to the party last week.**
- Correction: "had gone" instead of "has gone."

2. **I sometimes wish that I will have another car.**
- Correction: "would have" instead of "will have."

3. **I wish my house were so large as John's.**
- Correction: "as large as" instead of "so large as."

4. **I wishes you had been at the meeting yesterday.**
- Correction: "wish" instead of "wishes."

5. **She wishes he will stop interrupting her whenever she speaks.**
- Correction: "would stop" instead of "will stop."

6. **I wish I didn’t say that to him yesterday.**
- Correction: "hadn’t said" instead of "didn't say."

7. **I wish I wasn’t absent from class yesterday.**
- Correction: "hadn't been" instead of "wasn't."

8. **I wish my sister will go camping with me tomorrow.**
- Correction: "would go" instead of "will go."

These corrections align with the proper use of expressed wishes in English.