Mods, misschien een sticky voor deze?
On the ICTDI, the most common things to be aware of:
Cracked Manifold. If you smell fumes in the cabin or at the rear of the engine block, chances are it has a cracked manifold. It's covered by Honda for 7 years or 125k miles - no quibble.
Rattling Timing Chain - if your timing chain is noiser than normal, specifically pre-facelift cars (facelift have revised timing chain design) then you may be entitled to a new timing chain (+injectors as they need to be replaced too). Although this is also covered for 7 years/125k bear in mind this is a £4000+ warranty claim and Honda will most likely want to go through your service history to ensure it's been maintained properly.
Slipping Clutch. In 3rd or 4th gear, give the car a hard run on full throttle... if the revs rise quickly when the boost kicks in and then slip back down again, your clutch is slipping. There are various schools of thought on why this happens, and Honda themselves have issued technical service bulletins to their service teams to check the settings on the cruise control pedal switch to check for play (causing the effect of riding the clutch). I put it down to a few different reasons including a poor pressure plate design. Most of our members (myself included) who have had the slipping clutch, found that the friction plate was like new when removed but the pressure plate had adjusted to the last setting. You could keep driving for a year before it definitely needs changing but you risk damage to the flywheel. Bear in mind also that flywheel failure is rare, but not unheard of. If your Honda dealer says you need the flywheel replacing, then ask them to tell you what the freeplay readings are. Best news is that a new clutch fitted from Honda is £585 fixed.
Fuel Filter and general servicing. The ICTDI is a rewarding car to live with. BUT it MUST be serviced ON TIME and with GENUINE HONDA PARTS. Period.
If your car is suffering from hesitation, and sometimes a glow plug warning light then chances are your fuel filter needs replacing. It's the cause of 90% of issues we see on the ICTDI on this forum. Please replace it with a genuine Honda item and then continue further diagnostics if your problems persist. Sometimes the filter just needs bleeding..
The only other thing to bear in mind when servicing is Oil viscosity. The ICTDI needs to be run on 0w/30 fully synthetic oil. Do not listen to any other advice on this.
If you can afford it, try switching to Shell V Power Diesel - this engine does appreciate it.
Headlamps fogging up. Honda added clips to customers cars if they complained and shoved some silicon bags inside the unit to help clear any condensation. It was a cheap and poor fix and not great but it helped a bit. Mine still fog up in the corners on wet days but soon clear. I've seen some that look like it's been raining inside their lights..... Look for tide marks on the clear plastic cover at the front
Aside from this, things common to all Accords are issues with paint (very thin paint causing stone chip damage), some brake related problems on the rear of tourers due to collapsing brake hose... and from the top of my head.. that's really it.
On diesls, check the VSC (Vehicle Stability Control) light on the dash comes on with the ignition and then goes out (can also be switched off manually with a button to the right of the steering wheel). Can be very expensive to fix (£1k) but sometimes it's a wheel sensor. Not a problem on the petrols.
Sensitive to wheel alignment and tyres, check for uneven wear. A four wheel laser alignment is worthwhile. Umpteen threads on tyres, noise is often the biggest issue.
Clonking suspension could be anti-roll bar bushes. Lower arm bushes can also wear out, but difficult to feel, visual inspection can tell if they've collapsed.
Check clutch fluid reservoir. If it's black will benefit from a bleed, but may need clutch master cyclinder replaced, especially if the biting point is also very low.
Exhausts last a long time but genuine replacements v. expensive unless you happen to hit an offer/discount. Decent third party/fast-fit replacements hard to find. Custom stainless often the way to go and not too bad price (£300 or so).
Rear brakes on tourers prone to seizure, can often be freed off, but sometimes the caliper needs replaced.
On tourers make sure the electric tailgate where fitted works. Can be impossible to open tailgate if it goes and fixes can be expensive. Sometimes can be fixed with new support struts. Battrery off reset can get them going again short term.