Unfortunately my 1992 2.5L failed CA smog today, due to high NO (see pic). Anyone have experience with lowering these numbers. The shop said they think it may be due to an exhaust or manifold leak and we’re willing to confirm this for a $250 diagnostic fee where they would put peanut oil smoke in the system and look for leaks. I went home and connected my shop vac to the exhaust with duct tape to seal it and then let her blow. I sprayed soapy water and found leaks at the rear of the manifold. I am torn on whether to repair it or move on from the vehicle. I am sick of CA smog as my Jeep is running great otherwise.