R107

Failing R107, W116 and W126 V8 Fuel Delivery Systems
Don't think yours is ok. Get under the rear and visually inspect it.
The M116 and M117 V8's survived production for over 20 years (1970 to 1991), so now these engines are all 30 to 50 years old. The rear fuel delivery system is an important part of these engines and it is often neglected even by professional mechanics. Recently I have seen two cars that had their fuel pumps replaced professionally, but the old fuel hoses were not changed! Every single one of these old V8's I have seen in the past 5 years needs something done back there whether it be for safety, reliability, or performance. Once again, if you want it done right you need to do it yourself.

New Ways to Thoroughly Clean Gas Engine Fuel Injectors
Many of the older injectors will need to be "back flushed"
Not all older MFI and CIS fuel injectors are "restorable." Some are just plain worn out. If the tip is worn out or damaged there is nothing you can do to repair that. There are no replacement parts available for Bosch mechanical gas fuel injectors. You can not replace the tip. The fuel injector is sealed up tight during the manufacturing process.