i have a 1995 monte carlo, it has been a great car, i ran it every day. i had some events happen that made me be away for 3 days, i came back to where i live and started my car, and the top end, i believe it to be the valve train was knocking. this was odd. so I drove it that day too and from my destination. afterwords, i concidered the car toast, becasuse of how bad the knocking was, i pulled it into the back yard and there it sat. one day about a week later i got currious and i wanted to revieve the car. so i started it up and it still knocked. i heard of this mirical substance caled seafoam, so i decided to change the oil filter, removing the baffel inside the filter, and added 2 cans of sea foam, after about 10-15 min of idling, the car sounded abit beter, the knocking got quieter. so itook it for a spin up and down the stret to warm up the engine and get everything flowing. After about 10 min it was back to normal, NO knocking, no noise, engine was flawles. any clue as to why this intermitant problem is occuring, and any clures other than add seafoam in the oil evey time i want o drive it? what component might be causeing this, i have no idiot lights coming on , and no check engin light appearing. car works in all gears, and makes no noise after it quieted down from the addition of seafoam? please help i want to know if this car is really usable or if i am wasting my time.

thank you Jacob