90 Honda Prelude

We bought my son a 90 Honda Prelude that someone had swaped the motor, its a 2.0, the car has 225,000 miles it ran fine for the first year and then all of the sudden it won't start or won't let you put it in gear from park (you have to use the override on the gear shifter. We've had it to Honda 5 times for the same thing. Each visit costs about $500-$700. They can't seem to pin point the problem. So far they have, change the shift lock solenoid change oil replaced plugs, dist cap and rotor, set timing, idle. New v/c gasket, plug tube seals, grommets. 2nd visit replace ecu with used ecu, replaced tw sensor and radiator cap for idle surge. Did BG egr service kit (clogged egr ports in manifold) and bg fuel intke/injection service (very carboned oil & filter changed to chemicals w/ bg svr.
What happend after these two visits is the car ran for 3-weeks and then started back into the same routine of not starting and having to use the shift lock release. 3rd visit they replaced the brake light switch for ingnition interlock intermittent release. Adjusted fast idle valve. Removed intake manifold had egr ports machined a drilled, hot soaked to clean carbon. Egr flow normal now. Did 2 days cold start and 87 miles driving, no stall, runs good. Ha! Ha! 4th visit, still having the same problem not starting and then if it does start, when you get to where your going your stranded, because it won't let you shift out of park or start, now they tell me the car needs a new throttle position sensor (throttle Body) and gasket. So we have that replaced and sure enough the same darn thing starts happening. HELP ! What's wrong with this car? Someone mentioned the main relay. I'm not a mechanic but I can't afford to spend anymore money on a 90 Prelude. Please Help