Hi BKelley:
Earlier it was suggested that you change the MAP sensor. I didn’t see that you had it changed or cleaned. Or even checked.
Can you verify?
I cannot verify that they checked that. But I will put it on my list. Thanks for the reminder, and if you think of anything else, please holler at me!
Hello. I just changed the MAP sensor. No affect. I wonder, though. The vacuum hose from the MAP runs to a doohickey on the top of the engine. What is that part? I wonder if changing that might help. Also, the problem occurs more often when it’s hot outside as opposed to the winter months. What could cause that, that would be affected by warmer temps?
I thought the problem was consistent, technicians experienced the problem every time the car was road tested but could not diagnose the problem.
Let me clarify my earlier remarks. The problems happens in all drive modes, hot or cold. When it’s colder outside I can sometimes drive several miles before the engine stutter occurs, but when it’s hot outside (like it is now) I’m lucky I can go one or two miles before the stutter occurs.
I was thinking that maybe a weak vaccum hose somewhere might be the culprit but I wouldn’t know where to look or what to look for. Then I also thought maybe the doohickey the vacuum hose from the MAP sensor plugs unto might be worth a look. I did notice some teeth marks from what looked like vice grips on it.
Ever thought about posting a picture?? 
That’s a thermal vacuum switch.
Tester
I’ve been searching online, and so far I’ve seen that referred to as a MAP sensor filter or a gas filter. I cannot find any references to a thermal vacuum switch.
It is a filter, it prevents PCV gasses from causing sludge in the vacuum hose and sensor.
Is there sufficient air flow through the vacuum hose while the engine is running?
The MAP sensor input to the PCM can be monitored with a scan tool.
Thank you for confirming that. I get no check engine light from the MAP sensor, there are no error codes in the computer, and even at higher speeds it will not throw a code. The problem with my car, as described above, has stumped the mechanics at the shop. I replaced the MAP sensor today myself and there was no difference in how the car ran, but when I spotted that device I wondered what it was and if THAT could be the problem. So I’ve been searching online for any information on it. It’s hard to find though. Rockauto doesn’t have it, though I can find it on Amazon and eBay. 
So I’m gonna order the one from Amazon and see if that will fix the problem.
Again, thank you!
See, sometimes a pic is worth a 1000 words… Thanks for posting…
Now:
But did you see this??
and then this??
Have you at least tried to blow and suck air through the hose?? or even put your finger on the end of the hose at the MAP sensor to confirm vacuum??? Or you can just keep throwing parts at it and hope one sticks… lol
A little diag can go a long ways sometimes…
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Yep, pictures help. But in my defense, I didn’t know I could upload photos here. 
I don’t have scanning devices, so that’s out. As for checking for air flow, never thought of that but I can tell that part has been removed before so maybe it’s a problem past owners encountered? I dunno. If I try and remove it and for some reason it breaks off without a replacement handy, I’m screwed. So as long as the parts don’t cost much I’ll purchase them.
Thanks for your help!
If the hose is not flowing air or the filter is clogged, then you will be in the same boat as you are now… lol
And lots of pictures on the forum if you have looked around… 
Parts houses may let you use theirs, they normally use the better ones they are trying to sell (around here anyway)…
Or you can use a cheap hand vacuum pump to check for vacuum at the MAF sensor end of the hose…
I would also just unplug the MAF sensor (might/will try to stall on you, but you can work the throttle to keep it running at idle) and see if it helps any while driving… It should also set a MAF code…
I can safely say it’s not the MAP sensor. I changed it out, along with the filter on the manifold, and the problem persists.
Hi BKelley:
I’m sorry to see you “throw parts at the problem”. With a $100 scan tool (Torque Pro with your cell phone for example), you would have been able to determine if the map sensor was working. They can also easily be cleaned.
Hopefully you can end up finding the problem without throwing away more money.
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Unfortunately, the cars computer is not throwing any codes. So even if I had a scan tool, I doubt it find anything.
Please refresh my memory
Have you driven with the fuel pressure gauge hooked up and visible to you?
There was a truck in the shop a few weeks that would fall flat on its face when trying to accelerate
At idle, fuel pressure was perfect
When accelerating, the pressure dropped dramatically
I saw in late 2023 you mentioned a new fuel pump
What brand was it?
That was my point. A bad MAP sensor doesn’t always throw a code.
With a scan tool, like the $100 Torque Pro, you can check its behavior (engine off, while running, when you increase/decrease the throttle). Others here may have further ways to monitor a MAP sensor.
Plus they can be readily cleaned.
Sorry you bought a new one.