shihtzupug

My 98 Outback had over 200k and had a bad head gasket. It overheated, and when it cooled down, it wouldn't restart ( would crank but not start ) Rather than rebuilding, we opted to buy a low mileage engine ( same 2.5 ltr ) and installed it with no problem. Went to start it and had the same problem - would crank but not start. We've checked fuel ( injectors spray fuel thru fine ) , checked for spark ( yep, its there ) and replaced the ignition sensor and the computer. Same problem, will crank but not start. Sometimes when cranking it sounds like it could be off-time, but checked the timing belt, checked the crank and cam sensors and the timing marks are right on. We've run out of ideas of what to try next. Anyone come across something like this before ? It seems odd that the new engine would do the same thing as the old one did !