Sounds like you got a bad head gasket you can rent a tool that you put on radiator in pla,e of the cap that measures exhaust and you will know for sure
The T-Stat is located under the car up front just in front of the oil pan. Watch the video at this link, the owner in the video is replacing the thermostat housing gasket which contains the thermostat. Please be safe and support the car on a safety jack stand, never raise and work under an unsupported car unless you are prone to a death wish.
It could be the neutral safety switch if it is an automatic trans.On most cars you can disable the alarm by locking and unlocking the drivers door with the key.A mechanic would check for voltage at the starter, the neutral safety switch or clutch switch, and the key switch.
There are two common issues with the 2.2... Both relate to valve guides. If you're confident that the sensors and controls are functioning well. Knock sensor? it doesn't hurt to pull it clean its mounting surfaces and bolt before reinstalling it if you're certain that it's good - you may be retarding timing significantly if there's an errant signal there. This would be noticeable loss of power, but not "cut-outs" as in your presentation.
You may be looking at a hanging exhaust valve. The valves sometimes will 'hang' and not close as anticipated leaving you with a vicious stumble (a 4-cyl running on 3-cyl) two "causes", if you will.. The valves may just hang in the guide (sticky & tight from build-up) or the guide itself may be sliding in the head (unfortunately, a few of the 2.2's of this period do have this issue).
If you're interested in the diagnosis, you can drop the exhaust manifold at the head you can look at & compare how far the exhaust guides are protruding from the head - all of the guides should "sitck out" from above the exhaust valve the same amount -- if you have a loose guide they tend to be "out" a bit further -- The thinking on this for your symptom is that the guide will push out with the valve opening and NOT return far enough to allow the exhaust valve to fully close - the result is a loss of compression at various times/conditions that is hard to track down. The "fix" would be to R&R the offending head to press a new over-sized guide.
The other sticky valve issue is also not too uncommon, the diagnosis is less straight forward - in that you'd need to watch vacuum, power, and DTC data at the time that the this power issue occurs. Typically, I'd recommend going with a strong and safe engine-oil flush and some sort of strong induction/injection cleaning to try to loosen and remove any build-ups on the valves. Many people with the 2.2 have switched into Synthetic engine oils for this reason... Some discussioin have included a few of the "snake-oil" additives for use after the flush (the very thin "metal penetrating" kind of snake-oils get good comments in a lot of the discussions) - It's your vehicle, I find the flush and regular good oil changes can clear-up the 2.2's sticky valve issues without wondering what I've put into my crankcase.
