We just had the check engine light come on, and the engine was running a bit rough. It's also been fairly loud since we bought the car. Turns out, the exhaust gas recirculation system and all 12 intake valves were almost completely clogged with carbon. Remember that this is a port injected engine--that much carbon buildup on the valves is an achievement. Unless your EGR system is clogged, in which case, that is just bound to happen. If you ask me, EGR is something that really shouldn't exist.

 

Absolutely, the EGR system must be kept clean. Regarding removing it, it's a good thing nobody's asking you. EGR is an essential component of engine operation, both for emissions control and for long-term engine health.