I just baught a 2004 ford ranger fx4 off road 4.0L SOHC it has about 4000KM and its sounds like a spark Knock to me it makes a knock coming from the engine with it is going up a hill or if there is a load put on it and gets quite loud at times anybody have any ideas or help on this situation I have had it back to the dealer twice and they say there is nothing wrong with it what should i do
Thanks
FORDMAN2004

 

Sounds like your choice of gas to me. Try a tank of 89 or 91 octane gas and see if that knocking noise stops.

 

If i try a higher octane gas and it works then they should be able to adjust the ECU so the knocking stop because the book says not to use a higher octane gas it recommends against it

 

I've been running 89 Octane in my truck almost since I got it, and I get better gas milage while using this Octane fuel VS regular gas at 87 Oct. Go figure?
345 miles per tankful so far, and that's with a 4.0L SOHC V-6 and auto tranny and 4.10 gears. I never had any engine knocking with 89 or even 87 for that matter. Might want to try a different location where you buy your gas from.