Having problems with your 2003 Jeep Grand Cherokee ?
Codes p0351, p0352, p0353 and p1391. jeep won't start or runs poorly
The codes you mention 301-302-303 are all misfire in the respective cylinders. you should replace the coil, while you are at it also verify the condition od the sparkplugs.
Repair Help & Product Troubleshooting for 2003 Jeep Grand Cherokee
Tips for a great answer:- Provide details, support with references or personal experience .
- If you need clarification, ask it in the comment box .
- It's 100% free, no registration required.