2003 GMC Jimmy

Hello, your not giving us much to go on? Can you tell if your losing spark--fuel pressure, anything? Any codes? Around here some of the autostores will make house-calls, maybe you can get them to come out, check for codes.

Your loosing spark at the plugs? Are you losing anthing else? When the problem occurs, if your losing spark at the plugs-- injector pulse-- and other than initial prime the fuel pump doesn't run, then I might suspect an intermittent rpm signal. If your only losing spark then check that circuit. If there is a two wire primary connector at the coil, take it loose. Use an led testlite between the two terminals on the wiring connector, have helper crank engine, see if the lite pulses, if it does, everything up to that point seems to be ok. Then, check the coil--coil wire--cap--rotor.