Setting timing dakota 3.9 1992

After installing a new Distributor and coil, engine now backfires under a load, skips at idle and starts hard. It seemed fine at first but developed this problem shortly after I sold it. I did run it out of gas while using it in my yard. Is it possible I didn't line up distributor correctly. Without removing timing chain cover how can I correctly ck the timing and distributor position. The timing light shows 10 deg BTDC, wouldn't this indicate that I installed it correctly? Could the Dist. be 180 out of sync and still show right with a timing light. The original problem was that it would quit while at highway speeds but start right back up. I just sold this to somone and wish to help him find the problem.

When you set the timing did you disconnect the temp sensor just below the thermostat housing. Did you plug it back in after setting the timing. This is for older engines 1991.
Rotate the engine until no.1 cylinder is coming up to compression you can feel this with your finger is over the plug hole. The timing mark should be at zero.
Rotate the dist. until the rotor is at the camshaft position sensor cyl no.1 mark. on the switch plate assembly.
Depending on the mfg. date one of these methods should work.