More newbie questions (engine and cabin air filters, fuel injection cleaning)

[robothebobo]

So my new-to-me 2007 Fit Sport has been doing great after a few thousand miles (it's around 37,000 now). I took it for the first oil change the other day, bringing my own filter (a WalMart SuperTech, which is apparently a good filter). The shop said that I needed to change the cabin and engine air filters, and that the fuel injection system needed to be cleaned. The last item was quoted at $60, I didn't ask about the other two, since it seemed that I could easily replace those myself. Anyway, i politely declined all the extra work aside from the oil change.

Unfortunately, i'm in the situation of not having any clue if this stuff is needed at all. The mechanic showed me the cabin air filter, which looked OK to me (a bit dusty, a couple bugs on the filter), but which he described as 'filthy, needs to be changed immediately'. The AC has been working fine, IMO, though. Plenty of air flow..

As for the engine air filter, the only ones I can find online are K&N ones that cost about $40. Is that about right?

Finally, do fuel injection systems really need special cleaning? I did notice that under harder acceleration, there would be a sort of slight rattling noise from the engine compartment. Could that be a sign of dirty fuel injectors?


Thanks!

[Texas Coyote]

The rattling could be caused by either dirty injectors,or bad fuel with lower than recommended octane causing detonation of the fuel before the spark plugs fire.... Any ad to the tank fuel injector cleaner and getting on and off of the throttle at higher than normal rpm on occasion will take care of the injectors.... Buy fuel from a high volume station that sells a brand name product.... K&N filters are great and last forever, but you will have to clean and oil it periodically... Every 25000 miles unless you live in a very dusty environment but most people clean them sooner and K&N recommends 50000 miles.