VW Polo P0106 and P0172: The Timing-Chain Fault the Scan Tool Didn’t Name
A three-cylinder Polo case where MAP contamination was real but dynamic cam/crank phase movement proved the remaining timing-chain fault.
Tag P0172
Toyota Celica P0172: How One MAF Read Rich at Idle and Lean Under Load
A 2ZZ Celica fuel-trim case where the same contaminated MAF overreported idle air yet responded too slowly and too little at wide-open throttle.