are you kidding me? how can this be?
 

I hope someone here is the genius we need.

Sunday we bought a 1995 honda civic specifically for the mpg. We filled it up, drove it home, filled it again and it seems we got 39.16mpg. WOOHOO!!
Well, he pulled in the driveway and the brakeline went. Ok, fine. Fixed that. Fixed the ball joints. Today we're off and running again. Shop guy says it's a clean little car. I had him look it over because the previous owner had done plugs and head gasket and water pump and timing belt and muffler, so I wanted to be sure he did a good job.

Well, he sent me a text saying the speedometer is off by 5mph and that he had only gone 85 miles and used nearly half a tank already. About 20mpg, possibly worse. He's still driving. Obiviously he could stop to and fill it up to see if it was really using that much gas but he has a long drive each day.

Here I sit wondering how this is possible because we got it home Sunday, took it to the shop (and i love this shop) and today we're driving it. Between then and now, nothing has happened.

Then I got to thinking and I remember the seller saying he changed out the cluster from automatic one to a manual one. Perhaps that has something to do with the reading/displaying of information? Car has a total of 150,000 miles on it according to seller and he showed us the other cluster etc.

What are the forum thoughts on this? Is he randomly burning gas now or is the fuel gauge maybe off like the speedometer is and could it be related to the difference in clusters? Just seems so weird because it displayed fuel accurately on Sunday when we drove it 141 miles to get home.

Any advice appreciated.

Don't go by the stock fuel gauge. It is usually incorrect unless it shows full or empty. Tell the mechanic to fill up the tank and take a proper MPG reading next time.

lol.
the mechanic was redlining it the whole way!

i should have been clearer. the mechanic handed it back over to us yesterday thinking all was well. he "he" is now my fiance driving it again getting 1/2 of what he just did days ago. guess we were just hoping the auto to manual cluster was the issue. i've "heard/read" that they don't necessarily display data the same....which could also be the reason for the speedometer being off by 5mph.
ugh. here's hoping when he fills it up it didn't really use as much as it says.

I am sure the mpgs were not killed out of no where as long as driving habits haven't changed, or if anything broke.

It is called a "Honda Half tank". Fill the tank, it stays at F until like 70 miles, then drops to 1/2 by 130 miles, and hovers there until about 200 miles, then drops to E within the next 50-75 miles etc. It is extremely common with Civics.

That is true. I always almost have what reads an empty tank on the fuel gauge(touching the red line), I go to the gas station to fillup and pump 8 gal-8.5 gal in the tank. What do 5th generations hold? 10.9 I think.

Either 10.9, or 11.9. I think it depends on the model/trim. But right around that number regardless.

I NEVER go by my gas gauge lol. Always go by the odometer.

+1

My fuel tank tells me approximately how much I have left, my mental math tells me how much I really have. It's easy with KM's. 10L/100kms approximately $10/100kms (with leftover gas).

That whole gallon and miles thing you Americans do is crazy.

Yeah the standard system is stupid and outdated.....anywho

Definitely go fill up completely, zero the trip,then when gas gauge says you are almost out go fill up completely and divide the miles you drove by how many gallons you put in. BAM accurate mpg check