need help about had it my 2001 ford ranger 3.0 at 160,000 miles blew a head gasket so i figure i would just rebuild the whole motor and have the heads shaved and redone well i did all that new cam and crank sencers new injectors everything i can think of can still can't get it to run when i tore the motor down i didn't mark the camshaft synchronizer so i bought that tool i needed still not running right can get it to fire up and run but backfires any sugestions thanks