1986 240 -- gas smell and rough idle
 

I'm getting a smell of raw (not burnt) gas when I start driving. I smell it only when I roll down my window, and so I don't think it's coming into the cabin directly from under the hood. The smell seems to go away after a minute or two or driving. Also, it's been idling roughly -- wants to stall out and actually has once or twice when starting to drive but still moving slowly. Recently while it was in "Park" and idling very roughly, wanting to stall, I walked behind the car and was pretty sure I smelled gas from the exhaust. Been a long time since a tune-up or new fuel filter -- probably at least 20,000 miles.

There's also have an intermittent fuel delivery problem that I've been living with for at least a year. My best guess is something to do with the rear (in-tank) pump or a hose attached to it. The car will pulse, usually at freeway speeds, either surging or, more commonly, pausing as though I'm taking my foot off the accelerator. I've heard this is pretty common among 240s. Keeping the tank fairly full doesn't seem to matter.

I doubt if the two problems are related, but could they be? Best guesses? Will a mechanic just need to do a basic tune-up and then take it from there?

a basic tuneup will do nothing for a fuel leakage problem. you need to figure out where that fuel smell is coming from... if its from the exhaust, then you're running too rich, and you need to diagnose that. if its under the hood, you'd better find and fix it before your car burns to the ground at the side of the road.

stinky butt rich? bring it by somebody that can tell and ask them!

Actually, the gas odor seems to be coming from all around the car as I drive. At freeway speeds with window rolled down the smell is quite apparent, and I doubt that I would be smelling gas from the exhaust under those circumstances -- i.e., when I'm quickly moving away from the odor's source and in the opposite direction.

I did a visual inspection around the fuel injectors and noticed nothing other than a lot of dry-ish black powderness covering the exposed parts of the injectors. Underneath is lots of gunky oiliness that strikes me as normal.

I don't know if this means anything, but there's a round, C-shaped rubber piece at the top of each injector, where it connects to the rail. All four of those are loose and I can just turn them freely. It looks like they serve no purpose. Were metal clamps used on more recent 240s instead of what I have? (Mine is an '86.)

sounds dangerous. you need to find where your fuel is leaking before your car goes up in flames.

I noticed that where a hose connects the fuel line to the fuel-injection rail there's a half-inch gap that can be closed to tighten the connection. So with the car idling, I tried closing it. The idling slowed considerably and the engine nearly stalled. In the photo I've attached to this post the hose connection is toward the upper right. (Also, below the two rear fuel injectors you can see what I assume is oily residue.) Could this loose hose be the source of my problem -- i.e., the gas odor -- in addition to the rough idling?

Unless you see fuel leaking there when the engine is running, that isn't the cause of your gas smell. Don't get me wrong, you need to address it AND more importantly find the the source of the smell. Check around the fuel pump. Look under there while the car is idling to see if you have any drips. I have had to replace the banjo bolts on the exit of the fuel filter on both of our 240s. I live in the rust belt and rust ate away at the bolt till they developed a pinhole leak.

that oily residue could well be from fuel vapor leaking out around the injectors because the seals where they are inserted into the manifold are dried out and failed.

i suggest you stop what you are doing and bring it to a pro.