Bob,
If you haven't already done so, remove the bolt group, disassemble it, and clean it thoroughly.
Also remove the recoil assembly from within the stock and flush it out well with Gunscrubber, ether, or other pressurized solvent. Then relube and re-assemble using light oil as suggested above.
If the gun continues to malfunction, consider replacing the recoil assembly with an aftermarket one from Surecycle.