Just bought a 2006 Ford Escape XLT with 106k miles from an Auction. It has had extensive work done to the engine, but we are now a bit stuck. It runs rough, terrible MPG ( about 10mpg ) and has a check engine light. After pulling the codes one of them said the ERG Valve is stuck open. We are purchasing the mechanism which tells the ERG Valve when to open and to close (not sure what its called).
My question is could all these symptoms be due to the ERG Valve being stuck open, or is there likely something else causing the bad MPG and rough idle.
If the EGR valve is stuck open it causes a huge vacuum leak causing the engine to run rough and get terrible gas mileage. The EGR is a controlled vacuum leak controlled by the PCM and the input of other sensors.
The EGR valve usually gets caked up with carbon causing it to get stuck open. Changing the valve could fix your problem but further diagnostics may still be needed if the problem continues.
An EGR (Exhaust Gas Recirculation) valve actually bleeds exhaust gasses into the intake manifold to reduce combustion temperature, and therefore oxides of nitrogen. The valve stuck open is often accompanied by multiple misfires and/or a rich condition at idle. I quick check, if accessible, is to loosen the two bolts holding the valve and slide a business card or something similar behind the valve to block the passages, then re-tighten the bolts. If the engine then runs smooth, the valve is stuck open.