Follow up to re: mpg drop and loss of umph

From : jmc

Q: suddenly without warning jmc exclaimed 03-apr-07 606 pm my truck recently had a massive mpg drop - from almost 17mpg down to just a tad over 13mpg and i was noticing today that its lacking in power too - used to practically create g-forces when i accelerate now its decidedly sluggish. id written off the mpg change to the opal gas were forced to use in our vehicles here in central australia dont get me started -grr- but in short opal is unsniffable. it also destroys engines built before about 1986 but is *supposed* to be safe for newer vehicles snip jmc well turns out it was *only* the opal. but got to that in a roundabout way. called an autoshop one i wanted to try cause theyre closer than my regular one gave symptoms said id like to get my sparks/wires checked. she asked if i was using opal. yes. she said that id need a fuel system service cost au$220 and switch to premium and thatd put all to rights. after a quick convo with a clued coworker called my usual service center gave the same spiel. he immediately told me that *all* i needed to do was switch to premium - that the symptoms are only because of the fuel. didnt need any service. said something to the effect that you cant get high from sniffing it and neither can your vehicle i didnt get that right but close enough. he did say my truck probably needs new sparks anyway as the truck has 50k on it now and theyve never been changed. does that seem right end of story put premium in my last fillup. truck engine hasnt blown up as warned in my user manual. yea i exaggerate a mite and runs much much better. still too early to see whether the gas mileage returns to something reasonable... anyway i had noticed that all the propaganda about opal didnt mention two things performance and mileage. just kept saying how its safe for newer vehicles meets whatever requirements blahblahblah. everyone ive talked to whos used it is now reporting the same symptoms i experienced. every single one has noted reduced mpg or kilometres/100 litres if theyre aussie. most noticed a loss of power as well. hell i even noticed loss of power in the *lawnmower*! which reminds me. gotta go mow that 1/4 acre i now have before sunset. temps probably dropped down to 90 by now... jmc .