Low idle bad gas MPG Help ?

[fighiter14]

Hi, I have a 2000 ford explorer sport OHC with 246000 miles. I have had a low idle for awhile know but in the past two tanks of gas my MPG has gone done from around 300 miles a tank to 200 miles a tank. I replaced the IAC Valve with a standard motor product valve about a month ago because of rough start up and low idle. The idle was good for a day then started acting up agian idle around 500 rpms. Also just changed fuel filter about 3 months ago. I have not had problems starting up lately since the new IAC Valve. How do i go about fixing the MPG to get it back to what it use to be?? Any advice would be appreciated

 

[koda2000]

500 RPM is about right for a SOHC V6. though I personally found it to be a bit low. I turned up my throttle plate stop screw a little and that raised the idle to a tweak over 600, which seems better to me. Rough idle on the SOHC with that many miles can be due to a lot of things. CEL on?

 

[fighiter14]

The CEL light is not on. I dont know what it could be.

 

[koda2000]

Spark plugs? Plug wires? Fuel injectors? PCV valve?

I'd start with the spark plugs. Motorcraft ot Autolite brand, min double platinum, gap to .054. While the plugs are out do a compression test to evaluate overall engine health.