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Worse gas mileage after tune up

759 Views 22 Replies 11 Participants Last post by  sixsix
2001 V6 4.3 with body lift and oversize tires. 198,000. Ive always got around 16 mpg up to 192,000, then it dropped to 14 mpg.
One day it wouldn't start, turned over but wouldn't start. Moisture was getting in the cap and rotor during extreme fog conditions.( I've changed these several times over the last year, and still not 100 pct sure I've fixed that problem. Won't know till the next fog). Anyhow, when it wouldn't start I also changed plug wires, PCV valve, and replaced the plugs with iridium. I also replaced the fuel filter and air filter. The old plugs were horrible, so I expected my mileage to return to 16 mpg, or at least remain at 14, but instead it dropped to 12mpg.
(As a side note, my mileage dropped to 14 mpg when I got new tires installed, may be a coincidence, not sure). My tester reads no codes.
I have two questions, is it possible that installing iridium has actually made my gas mileage worse? Also, is it possible that IF my actual distributor is bad, it could be making the mileage worse? (If I get moisture in my rotor and cap again, my next step is to replace the actual distributor).
* Heads up, Im not a mechanic, I'm a 61 year old little lady who doesn't have the money to pay a mechanic to do this, so I'm learning about and doing lot more than I ever thought I would, or care to. I can now take the dog house off in 10 minutes, and put it all back in 30. I never wanted to get skilled at that. So with that in mind, please don't get too technical with your explanations, I'm not an idiot, but I'm not a mechanic either. 馃榿 Many thanks for your input.
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And I say take that Blindfold off when you do the doghouse/engine cover.
There have been quite a few responses covering the so-so obvious causes of mileage rate deterioration.

...and I seemed to have missed it, but maybe it is because of "Motor Is Tired" syndrome.
While I realize the 2 Vans are vastly different, at around 185,000 to 200,000 miles, these V6s start to lose mileage reputation.
And like our '92, your Van is probably fairly peppy, too, Right ?
And ours has not been raised or shod like yours.

Get off the gas, grandma ( LOL ), get better highway tires and start thinking about a mercruiser crate V6, if you intend to keep and demand high mileage, blah, blah.
Start dating a good mechanic... ( just sayin' ). I married into a smart med / hosp related family - if they are not doctors, they're nurses, etc.

LOL - Yeah, I know about those new distributers and getting them in there... ours is still sitting on our shelf downstairs in front of "The Idle Van".
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Tenzo said:
... maybe think about doing it in a parts store parking lot.... In my experience the gents just can't help but wanna be a hero
Bestest advice I've heard or read about in a while.

Jeannie says, "Heels help" - regardless of what you look like. Think Erin Brockovich.


"A SEXIST WOULD SAY"
My wife hasn't had a date since her hair turned gray either...
And I'm the one who talked her into quitting w/ the color thing.

Studley... good man. Pleasure is all ours talking to ya'.
Take care.


ps:
and breaking down on the side of the road is a 1st class ticket for a date round here.
...ya gotta' fight em off like grackels...

KENTUCKY
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