P0305 DCT 2005 Chrysler Pacifica AWD 57, 143 mi

My car was in an accident and they supposedly replaced a Vacuum hose to my cruise control and installed a harness. However My check engine light came on and the car has a small stall and putt. Took to the car to the Chrysler dealer, they explained the coils were fine but cylinder 5 was reading 100psi while others reading 175psi. Also stated injectors were fine. What else could be the problem? The dealer wanted to charge $800 just to look further to give a confirmation. I feel i am being taken advantaged of because I am a woman but I am no fool. Any advice as to further checks would be greatly appreciated. They didnt like the fact that I knew how to use my ignition to get the DTC code without paying. But hey, thats what I have a brain for.

If it's 75 pds lower in compression then the rest of the cylinders then the head has to be removed, you either have a blown gasket or a bad valve, both are common issues. I doubt it's 800 for further diagnosis, it's likely 800 for the head removal! You're not being taken advantage of you're being quoted the correct repair to fix the code. To be taken advantage of would to be sold a coil, an injector, a pcm etc before finding the low compression reading. The cruise control repair is not related to this but if the engine overheatted from the accident then it may have caused the engine issue and in turn the code.