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2002 Jeep Grand Cherokee P0201 and P0455 Error Codes - Multiple Misfire and EVAP System Issues

Model: 2002 Jeep Grand Cherokee Fault Code: P0455 Posted: 2014-03-18 22:02

My 2002 Jeep Grand Cherokee has been running fine until recently, when it started exhibiting severe performance issues. Initially, it sounded like a spark plug coil failure—so I replaced the coils. However, after one week, the problem returned, and new error codes began appearing: P0201, P0202, P0351, P0352, P-0353, P0355, P0300, P0302, P0442, P0455, P0306, P0307, and P0357. Additionally, the heated oxygen sensor bank is showing faults. I have already replaced all spark plugs and coils with OEM parts. The vehicle currently has 105,000 miles on it. After a visit to a repair shop, they claimed to have fixed the issue, but when my wife picked it up, it ran smoothly at idle but exhibited misfires during acceleration. A few days later, the symptoms returned—this time resembling a rocker arm failure. I'm now concerned about whether this is a wiring harness issue, engine mechanical problem, or something more systemic. I have no scanner to read codes in real-time and don't know if the technician who performed the used car inspection had any insight into these recurring faults. Could anyone provide guidance on how to diagnose or resolve this? The vehicle has been driven without major repairs since the initial failure.

Related fault codes
P0201P0455
Comments (3)
Anonymous 2014-03-19 06:22

Given the wide range of misfire codes (P0201, P0351-P0357) and the presence of a P0455 EVAP system code, begin with a thorough inspection of the wiring harnesses—especially around the coil packs and ignition control modules. Ensure that all spark plugs and coils were replaced using OEM or dealer-grade parts. If you purchased the vehicle from a reputable dealership, consider returning it for a full diagnostic and repair assessment.

Anonymous 2014-03-19 19:40

I've inspected the wiring harnesses myself and found no visible damage or loose connections. The issue appears to be more complex than a simple wiring fault.

Anonymous 2014-03-20 09:07

Your post — 'can any boy help or give me an idea' — seems a bit informal. Have you consulted the technician who performed the used car inspection? What engine type do you have (e.g., 4.0L, 4.7L)? Do you own a diagnostic scanner to read live codes and clear them properly? I agree with the previous comment: if you bought the vehicle from a reputable dealer, it may be worth returning for a full evaluation of these persistent issues.