95 Camry 2.2 Mechanic Is At A Loss

I replaced the head gasket. the car was not running right it would hesitate when you would let your foot off the gas or if you barley gave it gas. I Took it to a local mechanic the timing belt was off a tooth and they adjusted the throtle position sensor and timing.

It Drives great except when in park or nuetral the idle goes from 1k to .5. The other thing is that if you barley put your foot on the gas when driving it does the hesitation thing. That is where I am at with just those 2 problems.

The mechanic that fixed the first problem thinks it is a sticky lifter but I am not so sure.

Any Suggestions.