Contour Enthusiasts Group Archives Forums General Troubleshooting Lean fuel mixture

My 1996 Contour (65,000 miles) over-heated about six months ago and the head cracked. I had the engine repaired with a remanufactured head, new water pump, new thermostat, new spark plugs, and some other minor parts. Because it���?�s a double-overhead cam, my mechanic didn���?�t have the tools to get the timing perfect, so I took it to a Ford dealership and they corrected the timing with their special tools.

Then, several weeks later, my check engine light came on. The code was for a â�?��?lean fuel mixture.â�?� First, the Ford dealership told me to replace the two oxygen sensors (which I did). Then they told me to replace the Mass Air Flow sensor, which I did. Even so, the check engine light kept coming back on with the same code (lean fuel fixture).

The Ford dealership most recently told me that I have a small air leak at the intake manifold and that I need to replace the gasket â�?��?? or at worse, replace the intake manifold itself. My mechanic looked over it and couldnâ�?��?�t find an air leak. He thinks that the Ford dealership is just â�?��?guessing.â�?�

Anyway, my symptoms are a rough idle when I start the car in the morning. When it���?�s very cold (like today), the car is quite difficult to start and seems like it is not getting any fuel. I have to pump the gas to keep it running. After the engine warms up (3-4 minutes time), it runs well (but the check engine light remains on).

Any suggestions? Is it possible for the dealership to accurately tell me different causes every time I take my car in for service? I don't like replacing parts if they're just "guessing."

Sincerely,

Scott

"Could you elaborate - what was your mechanic trying to time - the valves?"

Yes. He was trying to time the valves. He checked on buying the tools necessary, but there were too expensive.

"Specifically what code(s) are stored, and did you look at the freeze frame data?"

The most recent code is PO171. The dealership wrote, â�?��?found air leak at intake manifold area.â�?� My mechanic said "the bolts were tight" and he detected no leak. He thinks the dealership is guessing, as I said. As for freeze frame data, Iâ�?��?�m not sure what that means.

Thanks for your help on this.

Sincerely,

Scott

I'm battling the same code in my daughters Zetec. Since you replace the O2s & MAF already there are two suggestions I can offer you:

1. Air leak, check as stated above. Also check the vac tube from your brake booster, as those have been known to crack or develope holes.

2. You have a '96, which have had wiring problems. check the wiring to the appropriate bank & O2 and see if the insulation is in good shape, unplug the O2 and clean the contacts within the connectors as best you can.

Best of luck

I had this same problem with my 98 Ford Contour, I had the mass airflow sensor replaced and all the gaskets on the manafold also replaced. The car ran alot better, although my check engine light just came back on with a P1151 code and now I have to change my O2 sensors.