my 2002 grand caravan 3.3l turns over but wont start,I replaced the coil pack,camshaft posistion sensor,crankshaft posistion sensor and one year ago i replaced the ecm,it turns over fine but no spark could it be the ecm or has it jumped time?

 

First thing I would do is get a scanner and check for active or stored codes. I would also check the ASD relay for power and ground. Or take the vehicle to a shop that has the tools to inspect your vehicle. You can't just throw parts at the problem and hope it fix's it.