Idle fluctuates after warmed up

[ryancod76]

97 EB 4.0 sohc
Starts up fine, no idle problems when the engine is cold. Drive to work and put it in park, idle cycles between 400 and 900 rpm. If I hit the accelerator, it comes out of it, then goes right back to cycling and I can smell gas. I also notice sometimes the engine shudders a bit when at steady speed, like a manual transmission when at slow speed in 4th or 5th gear. I was going to change out sending unit anyway due to dead fuel gauge, other than a fuel pump issue, what are some other things to look at. Thanks for any input.

 

[BrooklynBay]

Check the resistance of the engine coolant temperature sensor. It sounds like it's flooding the engine. Check the fuel pressure regulator for a ruptured diaphragm, and clean the mass air flow sensor.

 

[pcam13]

Check the resistance of the engine coolant temperature sensor. It sounds like it's flooding the engine. Check the fuel pressure regulator for a ruptured diaphragm, and clean the mass air flow sensor.

IIRC resistance on the explorer's temp sensor goes down when warm and up when cold. There is a diagram you can base your findings off of.

Edit: here is a link. --

https://sp.yimg.com/ib/th?id=HN.607988905140030795&pid=15.1&P=0

 

[ryancod76]

Thanks for the suggestions BrooklynBay and pcam13. I will post my findings when I check these components out.