Another drop in 'gas mileage'. This one is big.
 

I realize there is alot of threads on this already but I feel this one needs some more attention. My truck is a '95 4x4 3.0 (Just over 220,000 km or 136,701 M). Lately I've been getting around 14 -15 MPG city, and 17.5 - 18.8 MGP highway. Then tonight (just an hour ago), I go to do my calculation and WHAM, I checked and checked; but I read it and wept: I had a MASSIVE drop to 7.2 MPG (90% Highway)! Last time I calculated I got about 18 MPG. I don't have much experience with any vehicles but that seems like a mighty significant drop. Your thoughts?

Did you switch brands of gasoline?

Well, I did goto a station I haven't been to in a while but I've fueled up there before and had no problems.

unless you are leaking gas then something changed, either spark plugs, wires, timing, etc. How are the spark plugs? How are the wires? I think wires should be less than 25K ohms.

Are you sure you did the math correctly....

damn what a drop, you sure your calculations were accurate? Maybe you have a leak somewhere?

u sure someone didn't siphon your gas?

lol i was thinking the exact same thing

I've never checked the spark plugs, and I'm assuming they've been in there a while, but the truck ran well before. I have double checked my calculations and no mistakes there. I usualy take a picture of the odometer everytime I fill up, and then get my gas mileage by getting the difference in distance and dividing by the quantity of gas purchased. I've got the original lock on my gas cap, so I doubt someone siphoned some of my gas (if they did I'm assuming there would be marks around the lock). Well, I'll definitly look into checking the plugs, and looking up records of filter replacements etc.. I'm gonna check it out tomorrow in the daylight. I'll have to get myself some spark plug sockets and stuff and I've never checked plugs before :( but I've got a Haynes manual, and lots of info around the forums here too. BTW what do you guys pay for plugs, keep in mind im up in Canada so they may be a bit more$. Thanks for the replys thus far!

i used to be able to pop my lock with a pocket knife and u couldnt tell, just a thought, and have u checked ur air filter, it could be clogged causing that drop.

What is the temp where you are? How long are you letting it warm up>? it should NEVER be that low, run another tank (or even half) and see how it goes... maybe it was a freak incident.. or youre camera picked up a weird angle....

Lately it hasn't been too cold about -10-15 C or 5 - 14 F. If its really cold, say around -20 or below it revs at 2k and I usually let it go down to 1.5. Otherwise, I wait till the engine quiets down and the revs drop a bit. So say I let it warm up anywhere from 3 to 8 minutes. Ya I'm gonna see how this current tank of gas goes. I'm back to more city driving now so that will change it a bit. Do those Lucas injector cleaner products do anything?

I think lucas killed my truck.

But thats another thread. I would stick with Seafoam. Seafoam it (2 cans in tank, 1/3 - 1/2 can in brake booster vacuum line). Change the spark plugs. Change the wires. Go synthetic, Check the fluids. Check PSI in the tires.

Thats a good list.

I would run another tank and check your calculations, that's nuts.

Maybe an o2 sensor?

:saw: Well, I should have known. Turns out my calculations were off because the last station I visited, I didn't fill the tank.:hillbill: But that still means that I only got 11-12 MPG. (I was carring proably 150 extra lbs on the back end). I think I will do some more seafoam when it gets warmer, and check filters and plugs anyway. Thanks eveyone, I'm glad I screwed up and nothing was really wrong with my truck. :yotarock: