I own a 1992 Grand Marquis. Time after time my engine performance is getting lower and the car fuel consumption gets up. I can't keep up with speed even if I put my foot on pedal badly. I changed fuel, TPS, air cleaner, and spark plugs, and cleaned the MAF with a cleaner but my performance remains the same :(
Hi there, thanks for writing in. I’d be happy to offer my insight. I would recommend checking the EGR valve and EVP sensor. The EVP sensor will tell the solenoid to open and send vacuum to the EGR valve. Right after it does this, it looks for a voltage change from the EVP sensor. If it does not receive the proper signal, it should trigger a fault code. You should have a check engine light on in your dash.
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