I have a 1980 240 wagon that sat in a barn for ten years, only to be put on Craigslist and picked up by a friend of mine (I passed on it because my dad had put his foot down and told me not to buy any more 240s older than '86). He replaced a lot of big items on it, like the heater core, sender unit, fuel pumps, etc. He got tired of working on it while using it as a daily driver, so he put it in his garage and bought an '06 S40. Shortly thereafter, my '91 240 died, and I went against my dad's advice and bought the 30-year-old eggnog-white wagon; not only was he very annoyed, but he's never owned a pre-1982 Volvo, so he is often reluctant/unable to help troubleshoot its infinite quirks. In the last six months, I've replaced the exhaust, the head gaskets, and most of the engine/transmission mounts. For a while after the head job, it ran very well. Then it came to my attention that the fuel lines were made entirely out of rust. I took it to a local mechanic that has owned a few 240s in the past, and he replaced both fuel lines with vinyl-coated something or other, and when I got it back, it ran like crap. Starting it now requires turning the key while working the gas pedal like a pump organ, and even it idles as low as possible without stalling - so low that the dash lights start glowing, even though the battery charges well, the alternator apparently works fine (despite being the factory original Bosch) - and even once it's warmed up, it feel underpowered, especially compared it how it ran in January after I installed the IPD performance exhaust. It also has this lovely habit of jerking/bogging down suddenly, where I can actually see the speedometer drop 5mph as it kicks and bucks hard enough to give someone whiplash. Other odd issues include a very noisy fuel filter, a loud fuel pump, a speedometer that works but an odometer that doesn't (it had 137K when I bought it, but stopped at 139.25K), and an odd clicking sound that seems to come from near the fuse panel/clutch pedal area (though I haven't heard it recently). Also, the idle speed adjustment knob on the underside of the inlet manifold is baffling - the manual's instructions don't specify what turning it in either direction does, and I can crank and crank on that thing with very little effect.

With that said, feel free to shout out any responses you might have to any or all of the above. I'm getting pretty handy at keeping it at status quo, but nothing I do seems to improve it any.