Volvo Repair: Back firing at above idle, spark plug gap, hall switch

Question
Help I have a 1985 Volvo 240GL with 325,000, miles original engine and owner. The orher day It just quit going down the road at about 2000RPM.  I found the distributor cap broken and a piece of metal loose laying under the mag pickup.  I replaced the distributor and that solved the running problem it is fine at idle but as soon as I start opening up the throttle it starts to stumble and backfire, Since then I have checked compression 190psi across, changed plug wires and coil checked for bad grounds at computer by kick panel and intake manifold checked for bad connections at electronic ignition box,replaced fuel filter,disconected exhaust ahead of converter thinking plugged all ok cleaned out air filter tubing to throttle body replaced air filter, checked for camshaft belt timing, and spark plug gap. Thanks  

Answer
there may be a bent hall switch (window) inside the distributor, one of the wires might be in the wrong spot? 1-3-4-2 is the firing order. if you stand at the drivers fender looking into the engine bay, it is a clockwise rotation. if those two check out, i would insist that the distributor timing is off the crank, and the cam may be in time, but on the 240 the distributor is run off a gear that is timed as well.