'93 300SE (W140)

Car starts promptly when allowed to sit overnight. I get to work early (5:30), and if I go to lunch around 11am, it starts easily then, too. Leave for the day about 3:00 - also no problems. (Car is parked in a multi level garage which is remaining very cool this time of year, even with outside temps in the 80's).

I drive across town and park at a business - outdoors - where I do evening consulting work. Commute is 30+ minutes, highway driving, usually non-stop but there can be some stop-n-go.

Car sits until about 8 or 9pm. Turn the key and it will crank and "almost" catch immediately. Attempted restart with 3-4 seconds of cranking = nothing - not even a cough or sputter attempt at firing. Crank again and touch the accelerator a tad - fires right up as if nothing were wrong.

I haven't checked fuel pressure after this short sit, but I can't see how low FP after a short non-use period would be low, but after a long non-use period be high enough for prompt start.

I'm thinking something's heat-soaking and isn't happy.

The non-use time at night is about 7 hours in an enclosed garage. 15-min's in cool temps to work and another 5.5 hours sit in a cool garage. If I go to lunch it probably doesn't sit more than 40 mins wherever I go. Haven't noticed restart problems when attempting to return from lunch, but the problem is fairly new (3 or 4 days). Car sits again for 3 hours, again in a cool garage. Drive 30+ minutes in traffic - sit for 5.5 hours - restart is less than optimal.

It doesn't seem to be getting worse, but this is not ideal behavior.

Any suggestions?

ttt