Hey, Scotty. You rock! I was gifted a rough-running 3rd Gen 4Runner. It’s a 2000 Limited trim with the V6. About 265,000 miles. Live in the Midwest and it was sputtering badly this winter, backfiring through the airbox in the engine bay. Was running on the original timing belt and old plugs so I had the timing belt, water pump, thermostat, and plugs replaced. Thought it may have been out of time, with valves open during combustion due to backfire coming through airbox. Definitely running better following the service, but still happens intermittently a minute or so after starting (even when it’s run within the last hour). Removed and inspected throttle body and it looked good. Couldn’t get IAC valve off due to old Phillips head screws. Catalytic converter was stolen a couple years ago (at a service shop) and previous owner told me they replaced it with a sub-standard part. Toyota wants $4,000+ to fix the cat.

Not looking to make it a show car; just want to get rid of the sputtering without putting too much $$ into it. Any ideas?