VTECH Solenoid problem after accident?

Any ideas? 2002 CRV was rear ended 2 weeks ago. Mostly cosmetic, also had to replace part of exhaust. The day after I got it back from the shop, check engine light came on and car stuttered and decelerated rapidly at 2500 rpm. If I let off the gas and stayed under 2500, it would accelerate fine. Shop says it is VTECH solenoid and they cannot verify whether or not it is related to the accident. They say the insurance will not cover it. I have also had a few other smaller problems since I got it back that 'may or may not' be related to the accident. Can I trust this or should I go after the insurance company?