I have a 2000 Toyota Celica with about 180k miles.
When my car has been off for a few hours and I try to start it up, if I try to press on the gas (either in drive, reverse, or park) within a few minutes, it starts sputtering and sounds like the engine is about to stall. If I let the engine run for 5 minutes, I step on the gas, and off we go. Other times when I am driving, it sounds like it's doing the same thing when I press on the gas too quickly (like at a stoplight); if I ease into it, it's fine.
There doesn't seem to be any difference in cold or hot weather. The check engine light is on, and when diagnostics were run, the guy at autozone said the engine might be running lean. My brother-in-law (not professional) suggested cleaning the mass airflow sensor (haven't done this yet, since reading some horror stories of people trying to do this themselves). I've read around that the overdrive, which I always leave on, might be an issue. I've had the oil and transmission fluid changed, and it didn't seem to affect it at all.
Does any one have any ideas of what to do? Starting with the least expensive, of course, unless it's inevitable that I might have to spend an arm and a leg.