2002 Toyota Camry P0303 Code: Cylinder 3 Misfire - Diagnosis & Solutions

I own a 2002 Toyota Camry (4-cylinder, 40,000 miles, manual transmission) that consistently displays the P0303 diagnostic trouble code, indicating a misfire in cylinder #3. I have performed several troubleshooting steps, but the code persists. Steps taken so far: 1) Swapped spark plugs between cylinders — all appear in good condition; they are iridium-tipped and should last well beyond 40K miles. 2) Replaced ignition coils with swapped positions — I’ve heard that ignition coils on this model can be prone to failure. 3) Added two separate fuel injector cleaners to the fuel tank with no improvement. 4) Removed and cleaned the camshaft position sensor (CMP); no visible damage was found. A full drive cycle has not yet been completed post-repair. Current hypotheses: 1) Replace or reseat the camshaft position (CMP) or crankshaft position (CKP) sensors — these are known to be critical inputs for misfire detection in this model. 2) Inspect or clean the fuel injector for cylinder #3, as some sources suggest exhaust sensors like oxygen and air/fuel ratio sensors could contribute. However, I don’t understand how such sensors — located downstream in the exhaust system — would directly cause a cylinder-specific misfire code. My belief is that the P0303 code relies primarily on signals from the CKP and CMP sensors. According to my Haynes manual, other sensors typically trigger different DTCs, not this specific one. Therefore, I suspect either: - A faulty CMP or CKP sensor, - Or a clogged/dirty fuel injector in cylinder #3. Note: I am uncertain about the exact identification of cylinder #3 — I am numbering cylinders from left to right when facing the rear of the vehicle. I’m seeking advice on whether a compression test is warranted, or if inspecting and cleaning the fuel injectors should be prioritized.