engine stalling after removing load

ive got a 2001 toyota celica gt 5speed. engine is idling a little rough, but overall it runs okay. if i put load on the engine, for example holding it at 4.5-5k on the highway and then drop out of gear, the revs drop to below idle speed, around 500 rpms, and will sometimes stall out. other times it recovers and stabilizes, and then evens out from 1-1.5k. problem does not seem to be reproducable without putting actual load on the engine, revving it parked doesnt produce stalls, though it is possible that it simply requires more testing

cleaned the throttle body, replaced the idle control motor and throttle position sensor. what else?!

I would look for a vacuum leak somewhere first. The rough idle is a big red flag for them. If you have a vacuum gage, hook it up somewhere convenient and see if the needle jumps around erratically. You can find vacuum gage charts in repair manuals and I'm sure online too.

If you have a suspect component, spray around it with carb cleaner, if the idle smooths out, you found it. Spray around the throttle body shaft while you're at it. Don't douse anything, a little spritz will do it, avoid working on a hot engine, cool or moderately warm is fine.

Bob

Whack the EGR valve with the butt of a screwdriver. If that changes the issue at all, chances are your EGR valve is bad/stuck/full of carbon.