1989 Acura Integra Unstable RPM

Thanks hmac300 for your reply. Today when I was trying to start my car it started making a tin hitting noise and I noticed there was no compression in the engine, self starter motor running freely. After that I removed the spark plug from the engine and disconnected the distributor wire and cranked the engine and all four pistons were running but the sound was still there. I dont know whats the problem. Plz help me um in a very big problem this car is very important for me.

Thanks again hmac300 for ur help. I just came from the mechanic, first when I showed him the car he heard the same noise n told me like u did that valves are bent or timing belt is torn but when he checked the engine by removing valve cover and timing belt he said it is ok. After that he tried to start the engine for half n hour at last the car started but again the rpm started jumping from 1500 to 500 n then it dies. My mechanic told me he doesnt have any clue what is happening. Actually here in my country honda cars are rare Toyota rules the road, mechanics know the toyo engine very well. Oh another thing I asked my mechanic about the fuel pressure n he told me its ok. If u can plz tell me which part controls the rpm n pickup it will be very helpful. U have already suggested me some fantastic ideas without seeing the car.

Hello hmac300 how r u? Thanx a lot for helping me so much. I've tried out every thing what u have told me. I've checked every hose every pipe there is n sprayed carb cleaner in the bottom of the carb but with no result. Now my mechanic is telling me my ecu is dead or faulty thats why this is happening. My ecu is PR6 it has led light at the center. The led doesnt flash when I turn on my ignition or start the engine it only flashes when I turn off my ignition for a fraction of a second, is it ok? Any suggestions will be very helpful. Thanx

Thanx hmac300 for ur help. I know its a bit rude to ask u for help after u told me u dont have further suggestions sorry for asking for help again. Could u plz tell me there is a map sensor in the engine, mechanic is telling me thats the culprit the ecu is ok. Can I use toyota map sensor instead of honda in the engine is there any difference? It'll be very helpful if u can explain. There is three wires coming out of sensor its made by denso.

Thanx alot my friend for helping me out.