I have a 4.3l v6 1993 sonoma 4x4. And i have a wierd starting problem. The truck will take about 3 to 5 seconds of cranking to start everytime EXCEPT when it was started once recently or if its really really cold. When its really cold or has been started in last 20 mins it will start up soon as key is turned. Ive replaced fuel filter and spark plugs. I thought maybe a fuel pump but my friend swears its not. Any ideas? Thanks.