improved gas mileage?
 

has anyone had any experience with the so-called plug-in performance enhancers available, specifically as relates to improving gas mileage on a 94 v8 gas hog? any feedback would be appreciated. tks

Don't bother with any of those. The best thing to do is a full tune up all fluids including the diffs and brakes. All filters, lube up everything. Clean the fuel system to replacing the emission hoses replace plugs cap rotor plug wires ect.

tks for the input- i suspected as much

Wanna know how my mileage improved? (serious no joke) I was surprised by this as I was fearing the opposite. I have a 94 reg cab 3.9 A/T truck. gets 17 on a good day.
I recently bought a 93 clubcab with a 318. bigger engine. same 3.55 gearing. bigger truck (club cab vs reg cab) the club had a supposed bad tranny. (auto)
I swapped in a 5 speed behind the V8. Now I get 17 on a bad day and 20 on a good day.

keeping the foot out of it is primary. I found ethanol free gas is working wonders. It has gone up from 16.5 to over 18. 5.2M 5spd.

assuming you put the correct tranny behind the 318 (NV3500) then yes. Ive read alot actually that the V8s tend to get slightly better gas mileage than the v6. i beleive it is a combination of engine power/vehicle weight ratio and the higher ratio's of the transmissions that were used behind the V8s (NV3500 is geared higher than the AX-15 of the V6)

yes I did put an NV 3500 in behind my 318. as well as the computer from the donor truck; but though I hear all the horror stories I wouldnt have been afraid to pop an ax15 in if that was what I could have found;

and I wish I could FIND ethanol free gas there is no such animal here in Illinois

it aint worth driving 40 miles (80 round trip) to fill up thats the closest 2 stations to me.

to the OP what kind of MPG are you gettin? What are you calling a "gas hog"?
Make sure the tuneup parts are in great shape or replace them, and dont use Bosch platinum, oe any multi electrode plugs they are a waste of money.
Converter could be clogged
trans could be slipping
driver could be driving it crazily

Bosch Splitfires actually work very well with our motors, just like it's been said..expensive...buuut my old man put those in before i changed them out so it wasn't my money wasted lol.