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Older Sienna's chugging, then acclerating; mechanics baffled

I’ve spent a lot of $$ trying to fix a persistent problem on my 2000 Toyota Sienna CE van. Engine chugs at idle & low speeds, then accelerates suddenly (when rolling, in gear). Have tried: changing timing belt (+ water pump), cleaned fuel injectors, replaced all of these: crank sensor, fuel filter, spark plugs & wires, ignition coils. $1800 later, nothing has worked. My usually spot-on small-shop mechanics (2 different shops) are baffled. It still (sorta) runs, but the sudden acceleration is a hazard in traffic & it’s not reliable–maybe not even safe anymore.

Local shop ran full diagnostics at our expense. Code results: PO 301, PO303, PO305, PO1717, PO171, P0172, P1130, P1150. Translation: Cyl.s #1,3,5 misfiring. Fuel trim lean, bank 1; rich bank 2. (This prior to sparks & wires replacement.) They recommended replacing both A/F ratio sensors, which would run another $700 (at their shop, book rate). Did not authorize repairs, as I don’t trust this shop & my other mechanics doubted this was THE cause of this problem. Reluctant to spend another $700 if that repair is not likely to resolve this issue. Any ideas?

Clean MAF, clean or replace the IAC and check the TPS for electrical flat spots or less than smooth resistance increase with VOM

Thanks, Benny. But please, could you translate the acronyms? I have no idea what those initials stand for. (I’m not a technician, just the car’s owner & not very literate about such things.)