I used to own a 83 celica with the 22re, I noticed the idle was shifty then on occasion id see white smoke in the rearview mirror, then all of a sudden one day the temp gauge went towards the red quickly and (because it was my only car) i drove it a couple more times reluctantly and the idle got rougher, and it was billowing white smoke like Uncle Buck, I could smell the antifreeze in the exhaust, which is typical of a headgasket, i took it in hoping i hadnt cracked the block or warped the head and was fortunate to only need a new headgasket, basically if you experiance someting close to this you should take it in and stop driving it, the 22re is a badass engine but will only handle so much, also beware even with a bad headgasket, the 22re can hold great compression, i took it in for a look at the first signs of overheating and they did a compression check, but because the comp. was so solid they ruled out the HG.,
hope this helps