1997 With Multiple Codes
 

My 97 has 4 codes. Before I start throwing parts at it, I was wanting to know if anyone had any suggestions on other remedies. It will barely run 60mph with the engine light on. I can reset it and it runs great. It will come back on after driving awhile.
P1506-Idle Air Control Overspeed Error
P1443-Evap Emission Control System Valve
P0420-Catalyst System Below Threshold
P0141-Bank 1 Sensor 2
I have just replaced the front O2 sensor.
Any tips before I start buying parts?
Thanks

Welcome to the forum

P0420-Catalyst System Below Threshold
P0141-Bank 1 Sensor 2 <<< this is the rear O2 and its a wiring issue, check if wires have touched HOT exhaust pipes and melted, if you also had P0135 then it would be a blown fuse

These two codes may mean your exhaust system is clogged up, partially blocked, which limits RPMs/power
If old air/exhaust can't get out then new air/fuel can't get in
You can use a vacuum gauge to test for this, but the codes may mean Cat converter has broken up inside so thats why the exhaust can't get out

You can also pull out the upstream O2(front) and go for a drive, it will be loud, lol, but if you have power back then exhaust IS clogged

P1443-Evap Emission Control System Valve
This won't effect engine performance, but should be addressed at some point, especially if you have to pass smog tests

P1506-Idle Air Control Overspeed Error
There is the IAC Valve on the upper intake by the throttle plate, computer uses this to set idle RPMs, it can be cleaned, read here: https://www.explorerforum.com/forums...-w-pics.84220/

Yours will look different but same to clean
If you replace it, it MUST BE with is Motorcraft or Hitachi brand IAC valve, other brands won't work well in Fords

And this code can be from a vacuum leak
After engine is fully warmed up, let it idle
Unplug the 2 wire connector on IAC Valve, it should close
RPMs should drop to 500 or engine may even stall, either is good it means IAC Valve moved/closed, and there are no vacuum leaks

If RPMs stay high then either IAC Valve is not working or there is a vacuum leak

Thanks for taking the time to write that detailed response. I will give your suggestions a try today.