2007 Toyota Camry P0355 to P0351 then P0305: Spark Plug and Coil Replacement Issue
I own a 2007 Toyota Camry with a 3.5L engine, currently at just over 100,000 miles. The check engine light and traction control light both came on unexpectedly. After connecting a code reader, I found the initial fault was P0355 — indicating a misfire in cylinder 5 of bank 2 (the rear bank). To diagnose further, I removed the intake manifold to access the back bank cylinders. I replaced spark plugs for cylinders 1, 3, and 5, then swapped the coil pack from cylinder 5 with one from cylinder 1 (which had no misfire code) to test if that was the root cause. After reassembly and clearing the codes, I started the car and began backing out of my driveway. The check engine light immediately came back on, now showing a P0305 code — indicating a misfire in cylinder 1 (front bank). After replacing the spark plug for cylinder 1 and swapping it with a known good coil pack from another cylinder, the engine ran rougher than before. I'm now wondering what to check next. Should I drive the vehicle for several miles to see if the code shifts to cylinder 1’s original coil? Or is there something else I should inspect? Any guidance on diagnostics or potential causes would be greatly appreciated.
Do you have a scan tool that can read live engine data (such as fuel trims and oxygen sensor readings)? If yes, please share the short-term and long-term fuel trims at idle and at 3000 RPM. Also post freeze frame data for the P0305 misfire event and any cylinder-specific misfires. Does the check engine light flash when driving? If so, avoid driving until the issue is resolved.