Why does my Bronco need premium gas?

[esm]

Hi,

I have a '96 302 Bronco. For several years now I have to buy premium gas because everything else causes it to ping badly under load (uphill).

I have replaced the plugs, wires, cap, rotor and I have checked the timing, which is exactly at 10 degrees (original factory setting). What else could be done to get back to normal gas?

Thanks,

Ed

when you adjust the timing it must be done with the spout connector removed. i would also scan for codes , could be something else wrong and you may also have a vacum leak somwhere

[agin2000]

come again? (spout connector removed) whats spout connector and why it most be removed on timing adjusting????

[2facedbronco]

Removing the spout connector sets the truck into base timing. So the computer is bassicaly out of the loop (no advance) You then adjust the base timing like normal with light/distributor adjustment. Then plug the spout back in.

[2facedbronco]

You may have carbon deposits in your combustion chambers causing hot spots under heavy load. How many miles are on the motor?

[agin2000]

wheres the spout connection?

[esm]

I did disconnect the spout.

The engine has 310k miles on it.

try running some seafoam thru it. you may have carbon build up inside the heads causing an increase in compresion ratio. that is a lot of miles on that motor and i wouldnt trust the timing marks or the timing chain either. i am willing to be one of the to have slipped giving you a false reading.

[esm]

What's seafoam?

As to the timing chain, I don't think it has slipped. The gas mileage and overall perfomance, which is quite good considering the 310k miles on the engine, would be noticeably impaired.

[havack]

Google seafoam and you will find out all you need on it. You might try and retard your timing a bit to cure the ping. Some Fords are known to want the expensive gas.