My 1997 Ford Expedition has a Rough idle and code p1726 on OBD II scanner. Need advice on where to look for problem. Power steering has been squealing for 2 weeks and nothing else.
Looking at the p1726 code definition and the rough idle I would be curious if the engine smooths out if the accelerator is applied a tiny bit. If it does, you might be able to clean the throat of the throttle body and the edges of the butterfly. This will increase the amount of air able to enter the engine and would in turn increase the amount of fuel. And ultimately increasing the engines idle speed. This is quite common on older cars and trucks.
If the engine seems to run rough no matter where the accelerator is, you may be experiencing an engine misfire. Once the misfire happens often enough the OBD II system will store a code. The code will pinpoint the exact cylinder/s causing the issue.
As for the power steering squealing noise, the first thing to do would be to check the fluid level. If the fluid level is full and the serpentine belt tests OK, replace the power steering pump. If the fluid level is low, repair any leaks and top off before testing.
- Ford Expedition Code P1726 – Insufficient Engine Speed Decrease During Self Test