Erratic check engine light!!

[az_cwby]

I just recently bought an 89 FSB with a 351w,been driving it for about 2 weeks and now the check engine light comes on like its shorting out, but only lights up when the engine is under a load (climbing a hill or passing) and always above 60 mph. I've also noticed my fuel mileage goes way down when it flashes. I tried to count the flashes but its not consistant. There seems to be a small power loss also.....any help???? :blink:

 

[bluesman17]

Oxygen sensor?

 

[az_cwby]

Oxygen sensor?

31177[/snapback]

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wouldn't a bad O2 sensor leave a code?

 

[miesk5]

take a look at the vacuum line at the EGR Valve Position sensor (EVP) - could be leaky - leaks internittently

look here at the sensor pic

http://fordfuelinjection.com/?p=10

"...This sensor mounted to the Exhaust Gas Recirculation Valve (EGR) monitors its position. The computer delivers less fuel and more spark timing when the EGR is open. Lowering fuel mileage and tail pipe emissions..."

thanks to Ryan!

 

[89Bronco58]

take a look at the vacuum line at the EGR Valve Position sensor (EVP) - could be leaky - leaks internittently
look here at the sensor pic

http://fordfuelinjection.com/?p=10

"...This sensor mounted to the Exhaust Gas Recirculation Valve (EGR) monitors its position. The computer delivers less fuel and more spark timing when the EGR is open. Lowering fuel mileage and tail pipe emissions..."

thanks to Ryan!

31208[/snapback]

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Id say egr

 

[American Rebel]

Well, my EGR is not working at all, and there has been no change in my gas mileage or a loss of power.

Usually the computer sets the code if it is something serious, that can affect the driveability of the vehicle. Sounds like a fuel pump about to go bad.

Check the fuel system first, make sure all the pressure regulators are working properly. If the engine has a loss of power during High RPM, then it sounds like the fuel pump is not meeting the demand of the additional fuel.

EGR would only affect you if you don't have one at all, and the lines are just hanging there. I installed a bypass valve on my exhaust pipe next to the EGR, and it just blows the exhaust out back down into the catalytic converter.

I've noticed lately that my check engine light flashes for like a split second, just a quick flash. But, I haven't noticed any difference in the performance of my bronco.

I hope that helps...