Never stops shaking?
*NOTE* This is a pretty long post cause I feel context would help describe the situation.
So I have my 2000 Celica GT-S, it's mostly a daily driver, and only 166000km on it (I'm Canadian.. :O). I'm the third owner of the car. We had it inspected before we bought it, and it was perfectly fine at the time.
Anyway, so about a month or two after I became owner and started driving regularly the Check Engine Light came on. Not having a code reader, and minimal mechanical experience, I brought it to my mechanic to check out. He said the engine was misfiring, and just to watch it or a while.
I got the car back, and for about a week later, it came on again (at the time, I never really pushed the engine very hard, 3500 RPM at most.) He said the problem was the same, and that we'll start by replace the spark plugs. He finished, I took it for a drive, and things were good for a while.
A month later, the head gasket went, and we had to replace it. About a month after replacing, I could still feel the car shaking a lot while I was idling. Compression was still low in Cylinder 2 (compression in all cylinders was 175 130 175 175), so I brought it back in, and he lubricated it.
This is the weird part. For about 2 months, it was perfectly fine. After those 2 months, the light came on again, compression was still low. Sick of not having my car so often, I just figured I'd live with the light for now. After about a week and a half to 2 weeks, it turned itself off. It didn't shake at idle, no chattering from the engine, nothing. It ran smoothly, and quietly, and it stayed like this until today (about a month).
Today, I parked, and stayed parked for a good 15-20 minutes. I started my engine to move my car so I didn't block traffic or get ticketed, and the light came on again. I immediately felt the car shaking, and the engine was chattering again (A/C was off, I know that there's a problem with it being on that contributes to the engine chattering.) I let the engine stay running, then I drove for a bit. At every stop light, the shaking lessened it seemed. I would occasionally turn the A/C on, then off again when the cabin was cold, and the engine would stop chattering. The chatter would come back for a bit (no more than a minute) then disappear again.
Would anyone know what's happening? I don't know much about mechanics aside from the very basics, and I'm sort of concerned and wondering..