If the ECU can't communicate w/knock sensor, it won't be able to pull timing if/when pinging occurs. Bad pinging could be interpreted as a misfire, I think.
The ECU might decide to play it safe and retard timing as a default. This can cause driveability issues.
Have you tried reading codes...
I aggree with KMT. I think if the ECU, loses signal from knock sensor, it defaults to a timing stratgy that keeps the timing retarded all the time. It wont cause a miss, if anything it will idle smoother with the retarded timing, but it'll be down on power-may even make the exhast manifolds glow if driven hard/high r.p.m.
Read the codes for sure though, if you haven't already done that.You should at least get one for knock not sensed during the dynamic test. If no other codes stored, basic plugs, wires & compression check is a good place to start & a good fondation since you don't know the history of the engine/car.
One of my Turbo Coupes(2.3) had a low power issue only when coolant temp was below 140, which I determined was caused by retarted timing & by unpluging the knock sensor- they are only singal wire & only send a ground signal to ECU when it sensed a knock/detonation/ping. Leaving it unplugged restored the timing to normal & the power returned. What we think was happening was too much piston to cylinder wall clearence was causing a piston slap until it got warm enough & the knock sensor was misinterpiting that noise as a knock & pulling 8 degree's timing out of it.
