Hmmmm. This is getting more complex w/every post. Periodic stink, bad MPG, rough idle and of course none of it happens when it is at the shop. Temp was 40 deg. plus, what is it usually? Maybe one of the expensive innards of one of the cats has deteriorated/shattered and is partialally blocking the exhaust when you hit a bump or make a sharp turn? I feel as though I am reaching here. Anything else you can think of? Let me know.

does good when cooler... gets crappy when warmer...

is there an air intake temp sensor or some such business on that model that might be flaking and causing the engine to run extra rich?

maybe it''s the mass airflow sensor?

Makes perfect sense but no codes showing defective intake sensors, right?

sometimes sensors will go weak and not throw codes. BTDT, not fun to diagnose.

any luck?

Updated - Knock Sensor
 

Just a final update, not sure if either of you still frequent, yet issue last year
was a bad knock sensor. A bear to get to back of rear head, and also had exhaust
leak from rusted manifold bolt. So, ended up tearing down, and had heads
redone (valve guides, etc.).
Running w/ bad knock sensor, likely toasted the front cat., yet running strong...
well.... running yes, NOW stopping is the current problem this time.