This could be a shot in the dark but may as well try and help. I have a 2000 buick regal lse (3.
, after a road trip and getting into a traffic jam I noticed my car giving a bit of hesitation. Point is few days later drove my car to a gas station and it would not start when I went to leave, after trying to figure out what happened I tried to start again about a45 min later and it worked. Baffled me, it had symptoms of some type of spark issue hence the hesitation I mentioned which seemed to increase in tandem with the accelerator and as speed increases. Turns out it was a MAF (Mass Air Flow) sensor after getting a diagnostic check on my car. This brings myself to the second part in my post.
Is this something you could get checked with a diagnostic machine, I know it can cost $70-$100 but it could be better than going the trial and error route unless you have unlimited free access to a junkyard.
For anyone who has had a MAF sensor issue in the past I can tell you this with my experience owing a 3.8. the 3.8 can run quite hot as it is, this makes maintaining your cooling system all the more important. There is a coolant passage that goies from the LIM (Lower Intake Manifold) to the UIM (Upper Intake Manifold) that is supposed to keep your throttle body/air intake temp warmer in the winter to prevent freezing. In my opinion all this does is make your engine run even hotter in warm months, particularly on a road trip or traffic jam. This extreme heat will fry your MAF sensor and you may see yourself go through a few in your lifetime if you do not blow a head gasket and possibly cause worse damage to your engine cylinders first. I simply pipe tapped the coolant passage in the LIM that feeds your UIM, if I ever blow a head gasket my engine cylindars will not be damaged quickly because antifreeze coolant will have no way of pouring into my engine from the UIM.
Just some fun knowledge I though I may as well share.