When you say you had the ignition timing set at zero- do you mean you have the timing set to zero degrees (top dead center)? or do you mean that zero is the stock timing setting (10-20 degrees BTDC for most cars)?
You will need to use the timing setting on the underside of the hood. On some cars, you need to unplug a vac hose or electrical connector when you set the timing.
Lack of power is a classic sign of overly retarded ignition timing.
I don't think the timing is retarded at all. I adjusted it to tdc according to the marks on the crankshaft pulley. I have understood that the manufactures actually retard the timing 5 degrees. But I went according to the crank for tdc for each cylinder. I guess when I remove the spark plugs I could insert something or even use a pressure gauge to make sure it really is tdc. I actually advanced the timing a full 15 degrees and now it runs great and seems to have the power it had before. I guess I'll leave it for now but I still don't know what the deal is, since I've tried this adjustment about 4 times and each time I have to advance the timing to get it to run correctly. It is a possible retardation in timing or maybe my engine is just retarded or to be politically correct mentally challenged lol.
Under my knowledge the d15b7 timing is supposed to be set to 16 degrees, + or - 2 degrees if necessary. As the guy said above. Some models have additional notes on how to set the timing. Like on my car I have to jump (with a paperclip) the service connector under the dash to prevent the ECU from adjusting the timing while I'm doing it manually. This takes the computer out of the loop and allows an un-conflicted adjustment. The 15 degrees you set it to should be fine.