CODE 521 on a 1994 3.0

My check engine light came on today and after running a self check the code 521 came up. However there is no such code in my haynes repair manual. Can anyone help me out.:crying:

I don't have the FSM CD with me, but according to About.com (http://autorepair.about.com/cs/troubleshooting/l/bl_dtcs_54a.htm) the code means the power steering pressure switch did not change. When you go through the KOER test, there will be a point where you're supposed to turn the steering wheel. If that test was not completed, you could expect such a code. I'm not sure why this code would come up though under normal driving conditions.

-Rod

:runaround:This code came up during a self check. I didn't turn the steering wheel during the test though. The reason I did the self check is because the check engine light came on while I was driving. However upon doing the self check this was the only code that came up. Since then the light has not come back on but my car has no get up and go. It's like it's holding back. the gas mileage sucks too. I'm wondering if the fuel pump is weak because it seems to run a little better when it is full. when the light came on it had a 1/4 tank of gas in it. I've also been thinking the o2 sensors or catylict converters may need changing. I've replaced every sensor on the intake except the fuel regulator, coolant sensor. I've replaced the fuel filter, coil pack, full tune up, fuel system cleaning, even took the intake off and cleaned it and all ports. New egr and egr sensor as well. I'm running out of options.

So the light went out and when it went out, the car no longer has power? Or was the lack of power there before the light went out?

Do you have a multimeter and a fuel pressure tester with the Ford adapter? You say you've replaced every sensor on the intake except the pressure regulator and the coolant temp sensor. So what did you replace, and did you replace them looking for this issue, or over some period of time prior to the low power?

Does the engine idle smoothly or run rough? Poor fuel economy would indicate the car is running rich so low fuel pressure is probably not the issue, but it could be coolant temperature sensor, intake air temp sensor, Mass Air Flow sensor, oxygen sensors, engine misfire, fouled spark plugs, bad plug wires, cracked/broken vacuum lines, stuck EGR valve, intake manifold gasket, etc. You're going to need to do some troubleshooting.

-Rod

The following have been replaced: EGR, EGR sensor, mass Air Flow, Air temp sensor, Throttle position sensor, Coil (MSD blaster coil), platium plugs, plug wires, button and cap, K&N air intake, top intake removed cleaned and reinstalled, fuel filter, fuel system cleaning (2stage),

It seems that the motor is holding back on acceleration, a slight ping can be heard from maybe valves under hard acceleration. When I crank it up first thing in the morning it runs fine for a few seconds then it drops rpms and will sometimes cut completely off. Other than that it idles and runs smooth. When it does cut off I can restart it and it runs normal as well. I'm out of possibilities other than catilycs converters, o2 sensors, fuel regulator, or fuel pump

When I first replaced plugs it ran great for a few days and then it went back to the same thing. The gas mileage sucks and I did throw the codes for both banks 1&2 being lean.:runaround:

It's odd that the fuel economy would be so poor yet you're getting codes for banks 1 and 2 being lean. To rule out fuel pump and pressure regulator, I think you need to get ahold of a fuel pressure tester and see what the pressure is. That will tell you if you should spend time in that area. If you really suspect the catalytic converters are plugged, then you could try removing the oxygen sensors and see if you still have the lack of power. I don't really expect that installing new spark plugs would cause the converters to work fine for a few days unless the old plug were REALLY bad.

Another thing to keep in mind is that a continued rich condition will destroy catalytic converters in a hurry. They overheat trying to convert all the unburned fuel to water and melt internally. Since your fuel economy is poor, indicating a lot of fuel is going through the exhaust rather than to making power, you need to remedy that issue before replacing the converters if you find the converters to be plugged. Chances are pretty good converters by themselves will not fix a rich condition.

-Rod

I've been running plus gas instead of regular gas. I'm concerned about the slight ping on hard acceleration. Any ideas on that. I will purchase a fuel pressure guage tomorrow to see what the pressure is. Thanks a bunch :)