I bought my 89 3 years ago from a dealer with only 43,000 miles. It appeared to be stock. I knew it had a slightly ruff idle, but did not appear too bad, and seemed to smooth out above idle. I thought I could figure it out, and thought that I had several times during the last three years. If someone viewed my post, you can see that I have checked, adjusted, or replaced almost anything that can be. As time and mileage went by,i now have 50,500 miles, the problem got worse, until it was obvious to me I had at least a blown head gasket on #7. I hope this was the problem all along.

Here is question

Could it have had a small leak in head gasket the whole time, and it just got so bad it became obvious? At times in the past, I have had to add small amounts of coolant because low level light would come on. I did notice what looked like it could have been some type of stop leak liquid floating in the radiator coolant I had a 61 Rambler when I was 16 with cracked block. I think original seller traded it in with problem. If replacing both head gaskets doesn't fix problem, I going to have to get rid of it. I love this car( I had brand new 89 I ordered just for me in 89) but I cant keep putting money into it. I'm an honest person, so I won't try to hide the problem if I sell it.

 

Sounds like you found your problem now fix it.

 

I am doing that now

 

Pull you knock and plug out for a proper flush.