2005 Hyundai Tucson 2.7L - Random acceleration issues and hesitation

This thing has been driving us nuts! We're slowly but systematically replacing basically every relevant part suggested by the various codes it's thrown over the past few years, but it still acts up, totally randomly.

So far, we've replaced all the plugs, plug wires, coil packs, fuel pump, and crankshaft position sensor. I also briefly replaced the throttle position sensor, to which I didn't notice any difference either, but my roommate (the owner) thought that seemed to somehow make it worse so he had me put the old one back in. We do still have the new one though, and after what it did yesterday, I might put the new one back in soon. More on what it did yesterday a little later.

Still on the menu of other parts to check/replace are the mass airflow sensor, oxygen sensor, EGR valve, and camshaft position sensor (this model does have that sensor right?)

Anyways, what it did yesterday threw us both for a loop. While parked at the gas station and idling, he pressed the accelerator pedal, and literally nothing happened, engine RPM didn't change a single bit, even when he put the pedal to the floor it simply stayed at idle.

I wondered what the hell the computer was even thinking at that moment, like did the ECM just totally glitch out then or what? So I had him shut it down, wait about 20 seconds or so, and crank it back up. And sure enough it started responding to the accelerator again, as it has been for the past few years anyways.

I'm sure that it's at least partly related to the emissions control system, as the exhaust definitely smells like it's not burning all the gas (note that there's thankfully no visible emissions, just a notable odor), but why the hell would there be a random one-off where the vehicle wouldn't even respond to the accelerator at all until shutting it down and restarting it?

We'd go ahead and jump all in and replace all the other parts I mentioned, but ya know .. $$$ .. so we're tackling things as he can afford them and as we narrow down and correct obvious issues such as a few cracked vacuum lines that I've already replaced now.

Anyways, if you've read this far, thanks for your attention to this issue. If anyone has any suggestions or advice to help us find the issue and save our sanity, we're all ears! And thanks in advance.

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