(Occasional) Inability To Start Engine When Hot-Will Start Fine Upon 30-40 Minute Cooldown

Hi. I have an engine starting problem with my 95 Olds Cutlass Cruiser wagon-six cylinder. Although I have not had a tune-up in a while, the engine starts and runs normally just fine-perhaps just a bit rough from time to time, but generally fine. However, my problem first surfaced a year ago-July-in hot weather (I live in FL) when the engine is hot. Upon cranking the engine, the engine would not catch. We called AAA and I continued to try to start the engine-the starter would crank the engine, but the engine would not catch. After a while, my wife suggested that I simply wait and not try to start the engine, which I did (wait), opening the hood to aid in cooling off the engine. Just as AAA arrived, I tried to start the engine one last time(it had been cooling for 30-45 minutes) and it started fine. After that (July 2009)incident, I encountered the problem perhaps only 1/2 a dozen times in the last year, seemingly always in warmer-hot weather and seemingly only when the engine was hot. If the engine cools down for 30-45 minutes, it generally starts fine. Otherwise, when this happens, if I do succeed in starting the engine, it runs at a very rough idle-if I am lucky when this happens and the engine does start, I can rev the engine a little bit and eventually the engine will run more smoothly at idle and all will be well and I can proceed on my way. However, with the cooler(FL) winter weather, the problem seemed to go away. This happens only occasionally and only when the engine is hot and usually when the air temperature is warm-hot. The problem has happened twice in the last two months. My mechanic ran the car in his shop-when it did stall, he reported that it would start right up again-he suspected something electrical and did not think that a tune-up would necessarily solve the problem. Upon further thought, the last two times this has happened, my fuel was low(although I still should have had 3-5 gallons in the tank-my fuel gauge showed almost empty). My mechanic suspects perhaps an overheated coil or something otherwise electrical that works fine when cooled down. I just recalled the other day that the two most recent occurences of this happened, as I mention above, when my fuel was low. Would appreciate any thoughts. Thanks and best, Dan Deren

One additional bit of information. Because my fuel was low the last time this happened, on the way to my mechanic’s shop to have him attempt to diagnose the problem-see above-I bought 2-3 gallons of gas so, while the fuel tank was still low and certainly not full, it had more fuel than when I had encountered the problem the day before. Thanks for any assistance. Dan Deren

I assume the car doesn’t stall, but when hot and when low on fuel, on warm to hot days, if you shut the engine off, you will need to wait as long as 45 minutes to get the car to run again.
If this is the case, that old joke about the patient who complains about pain in the elbow when he plays the violin comes to mind (don’t play the violin).
You need to reduce the variables, which are a) a hot engine, b)a warm day and c)a low fuel tank. You can’t do much about warm days and a hot engine, but you can do two things right away that might help.
First, pretend the engine is empty when it is half-full. It seems that you have a collective habit of running the fuel close to empty before refilling. Not a good practice at all. The bottom of your tank is a cesspool of fine rust and oily deposits that can clog up your fuel filter and cause stalling. When the tank is mostly empty, the highest percentage of such gunk versus clean fuel is what is being drawn into your fuel line and filter. Not good.
Second, replace the inline filter. If you want to do it yourself (it is easy and cheap) read the owner’s manual to see is the car is equipped with a fuel filter shutoff and follow the instructions before attempting to replace the filter. If there is no shutoff, have your mechanic do it, it should cost maybe $50.

I suspect your mechanic is correct about something going wrong with the ignition system. I would check for spark when this trouble happens again.