1991 Ford explorer humidity problems

[drummer]

Let me start by saying i have replaced the fuel pump,relay,crankshaft sensor, and plugs and wires. The truck isnt throwing any codes and fuel pressure is fine. When the engine gets hot on warm humid days the car will not start until the engine cools down. I can sometimes get it started by holding the gas down while turning the key after about 10 minutes of trying. It then usually runs fine at highway speed, but whenever you slowdown or stop tries to stall. And has recently also run rough at highway speeds when it dips below 2000 rpms. Ive had this problem for two years please help!

 

[awood]

Holding the throttle wide open during cranking is one way to clear out a flooded engine on a fuel injected vehicle. I would suspect a bad fuel pressure regulator or leaking injectors. You can test for those. Search the forums here for procedures so you can prevent throwing parts at it.

 

[drummer]

I already checked the fuel pressure regulator and the leaky injectors don't make sense because the car is also acting up at highway speed now. It doesn't always start hard and run rough only when the car gets up to operating temperature