Was your car built on or after 8/92? If so, those cars are known to have engine wiring harness issues when they operate in hot climates.
As to the cleaning of the combustion chambers, I just went thru this quite extensively. Be advised that my diagnosis was arrived at by 2 top MBZ tech guys (one Corporate, one Regional) who went thru my car at great length (and expense!!). Real easy way to tell if you have carbon buildup....how does your car idle when you just start it cold (asfter sitting overnight)? Mine was definitely rough, so I ended up using several BG products to get things under control. Their "44K" product cleans the combustion chamber, and their "air intake system cleaner", which is a high-performance throttle body cleaner, I used inside the air intake. I actually removed my throttle body and cleaned it comprehensively (it gets pretty dirty). I then re-installed it and powered up the car without starting it; after about a minute the system resets itself and recognizes the new throttle butterfly position (its position moves slightly when you remove the deposits).
BG products are hard to get, as they don't generally sell retail as I understand it. However, many many Honda dealerships carry them, so perhaps that's one route to take.
After 2 treatments my car now runs perfectly. I'll use no other product; none even touched my problem.
If this works for you, do I get a part of the $3,400 the dealer was gonna soak you for?!? Just kidding...if there were that sort of payoff here, we'd all owe Benzmac, MBDoc, Steve, Aron et.al. millions!!
All the best, Michael