I had to replace all the brake lines including the proportioning valve because the car sat in a garage for 9 months. The engine had a terrible miss and would spit every once in a while. Could never tell if it would stall at a traffic light. Turned out to be a vacuum line. Runs excellent now.
A lot of reviews I've read on this vehicle talked about the poor performance of the 307 Olds engine, but I've found that replacing the vacuum lines and setting the timing gives the engine all the power she needs.
You had to replace all the brake lines because it sat in a garage for 9 months?
Was the garage under water?
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