'97 4.3 won't fire up in the morning only. A little history...installed new distributer, cap and rotor to resolve a misfire due to worn destributer gear. It runs great now...after you get it started.

Yesterday morning it wouldn't start at all, just turned over. Faint smell of fuel after a few minutes of cycling ignition switch. Fuel pump sounded normal and was kicking on. I get home from work in the evening and it fired right up on the first turn.

This morning it wouldn't start, checked for moisture in the cap - dry. Tried starting it again, it just turns over. I got my heat gun out and put a little warm air on the ignition module/coil assembly. It fired right up after applying heat to it for a minute. This no-start, heating and run-start happened within a minute or two time frame. So it looks like the application of heat to the ignition module/coil was the fix...which explains why it started fine after sitting in the sun all day yesterday.

...But why? EDIT: It's around 70 here in the morning and has been maybe in the 60's over night. It's a warm 75-85 during the day, so extreme cold isn't a factor.

Bad ignition module? Freeze it and have it tested? Suggestions?

 

Take it apart, you may have a cracked coil that moisture is affecting. The heat from the heat gun may just be enough to evaporate any moisture and cure the problem.

 

I installed a new ignition coil and it's been starting fine the last couple of mornings. The old coil looked to be sealed and didn't have any visual signs of internal damage. The reason I opted for the coil was that I heard a clicking that sounded like a spark arching the other morning when it was trying to start. I wouldn't think the ignition module would have a high voltage arch sound like that.

Only time will tell...