I checked this post, but it doesn't seem to indicate much regarding my issue: weather causing power loss

But I have the following vehicle: Ford Ranger, 2003, 4.0 SOHC Engine

Often when the weather gets warm, the vehicle won't start. Usually it turns over for a few seconds the first time I go to start it. But then after two or three seconds it dies. The starter will turn just fine, and the battery is strong. The battery always has plenty to keep the starter turning.

The conditions are generally going from a 30-degree F night, to a 60-degree day. Today this happened, and those were the temperatures. It started fine in the morning, when it was about 45 degrees, but then it warmed up to about 59, and that's when this issue happened (like it has in the past).

Everytime, it starts again eventually. Each time it takes longer to wait until it will finally start properly. The first time, it idled roughly for a while, and then died. It started back up about 5 minutes later. Then 30 minutes another time. Then 4 hours another time.

Last time this happened, I had it towed in, but sadly it started right up when the mechanic got to it. They checked the fuel system and said that everything looked ok. They suggested that I change the spark plug wires (the plugs themselves are new and in good shape), as maybe one of the wires is arcing over the valve cover gasket.

Usually this also happens when there is less than 1/4 tank of gas, but last time, I had over 3/4 tank. I have changed the three spark plug wires on the driver's side, but haven't gotten to the other three (it's a complicated job, and I ran out of time).

Can anyone please suggest where I should troubleshoot? Should I change the fuel filter? Or change something else?

Update: Today the weather is in the 30s, and the truck started up perfectly. I waited four hours yesterday, while the weather was in the 50s, but no luck starting it. I bought a new coil and will install it soon.

  • 1
    Does this mean it struggles to start when the engine is warm? Next time you go for a drive, turn the engine off and try to re-start it whilst it's still at operating temperature if you've not tested this. Sounds like humidity could be causing some problems. Replace the spark plugs and their wires (or coil packs if they're coil-on-plug) and then re-test. It sounds like it's something to do with the HT/Coil packs.
    – yollooool
    Mar 19, 2018 at 19:57
  • @yollooool Hi, it doesn't always struggle when the engine is warm. If it's a cold day, I can start and stop, and re-start perfectly, over and over. It's just sometimes when it becomes warm out, it won't start at all, until hours later, and then it's fine. It's as if the fuel is shut off.
    – Mark
    Mar 19, 2018 at 20:42
  • 1
    Maybe failing injectors take a resistance reading and compare it to when it doesnt start
    – Ben
    Mar 20, 2018 at 0:12
  • Any codes? Or is the Check Engine Light (CEL) illuminated?
    – CharlieRB
    Mar 20, 2018 at 18:51
  • @CharlieRB Hi Charlie, I don't have a diagnostic tool, but I'll check the CEL next time this happens and post. Thanks.
    – Mark
    Mar 22, 2018 at 18:54

1 Answer 1


This turned out to be a faulty fuel pump. The problem has been gone now for about a year.

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