I purchaesd a 1999 XJ 4.0 that had been sitting for a few years. I repleced the fuel pump when I drain the old gas. I replaced distributor cap, rotor, plugs and coil. I have not had any problems starting the XJ until recently. It seem like the colder it is outside the harder it is to start. I've search the web but I have not found any good solutions to the problem. Can you help?