[knightrider_916]

I recently replaced the wires and spark plugs in my 98 gt. I now have ford racing 9mm wires and new ford motorcraft plugs. I have always used 87, but my car pings when i get on it so.......I started using 91 and the pinging is gone, but my question is should my car be able to run on 87 with no pinging? Or is a higher octane better than regular in general? Or should I just go get it tuned?

 

[engineer76]

I recently replaced the wires and spark plugs in my 98 gt. I now have ford racing 9mm wires and new ford motorcraft plugs. I have always used 87, but my car pings when i get on it so.......I started using 91 and the pinging is gone, but my question is should my car be able to run on 87 with no pinging? Or is a higher octane better than regular in general? Or should I just go get it tuned?

Knightrider

Did you get the right Motorcraft spark plugs? (heat range)
Check with the owners manual. I had a set of Platinum +4, they were horrible, lots of pinging.

Regarding gas: I have the same problem than you do. 87 Octane just causes piging after the motor gets hot. Changing to 89 was all it needed for my 2000 GT. Looking up the owners manual of the 2000 GT it says something like "89 recommended" , "87 minimum required".
Since then I just run it on 89 - no probs.

 

[BlueStreak03]

I agree, double check and make sure you got the correct heat range plugs. If you did and you're experiencing the ping, you can either switch to 89 octane or drop down a range on the plugs.