I have a new mechanical problem. My 99 suburban is dieing at very random intervils. It will run fairly well for weeks or months then completely die suddenly like you shut off the ignition. The fuel pump has been making a high pitched whine for some time. I have noticed that when you floor the gas it shudders like its not putting out enough fuel pressure.( it showed about 50psi at highway speed with a gauge) The truck shows no codes no check engine. I have replaced recently;fuel filter, plugs, wires, dist cap, rotor, pickup coil. It could possibly be the fuel pump relay or the ignition module. :shrug: anyone have any other ideas? The fp is $265+ and I know a module is pricey as well.