I recently bought a 95 sc 5 speed. I have an intermittent check engine light along with a tach signal that drops to zero under accel, and returns at cruise but doesn't seem to always read the correct rpm. It has a rough idle and misfires under low rpm load and runs well under boost but will occasionally fall flat on its face under boost. I tried replacing the cam position sensor with no change in performance. I cant check the code because I dont have an obd I reader.