CUSTOMER CONCERN Engine runs rough at idle with DTCs P0016, P0089, and P228D, and the engine oil level is approximately three quarts low. CAUSE Inspection found the upper timing-chain guide failed, with the top of its bracket missing and grooves worn into the valve cover. CORRECTION Remove and replace the timing chain and correct the failed upper-guide condition.

CUSTOMER CONCERN The malfunction indicator is on with DTC P219A, no misfires are present, and long-term fuel trim remains in the single digits. CAUSE Flow testing found one fuel injector delivering substantially less fuel than the other three. Cleaning did not restore the injector's flow. CORRECTION Remove and replace the low-flow fuel injector, confirm the replacement injector matches the remaining injectors, and road test to verify DTC P219A does not return.