Engine Less MPG?

Less MPG?

When I first got the car, I was getting 300-350 miles between gas refills, but ever since I put in some Pennzoil 10W-30, it seems I've lost quite a bit of MPG and now I'm at about 275-300. I did the oil change a little late, at around 5500, but still dosn't explain it. Anyone have similar issues?

well if you just got the car you can't really tell from just 6-8 months.... i've had my car for a year ... and last year of this date ... i was getting more than 32mpg ... now i'm at 26-29mpg ...

I noticed a change in mpg after going to mobil1 but im going to do the next oil change with a toyota filter and see if the filter is the problem ...

i used to get 100 miles right on the first tick of the gas tank .. now i get 100 on the first dark tick ... go figure .... for sure i don't think it does 32mpg local ... i drove all local and got 26 .. big difference ... now that gas is 2.10-2.80$

I changed my oil w/ a synthetic top brand and it i have gotten alitlle better miles per tank than before

it's probably because you're running 10w30. The recommended oil is 5w-30. A heavier oil gives worse milage.

i use 5w30 ... it's on the oil cap right? i think it's my fram filter .. i'm going to switch with a toyota next time and see .... i got 32mpg last fill up .... it seems to be getting better ... could be the weather getting warmer ... we'll see .. i'm not getting the 40mpg i'm suppose to man!

Colder weather does affect fuel mileage but how cold does it get in SoCal?? Have you checked your air filter and tire pressure? Amsoil synthetic in engine and tranny did help too, as well as switching to Bosch Platinum 4 spark plugs.

tire pressure.. haven't checked that in the last 20k miles but i'm sure they do that when i get oil changes right?

my air filter looks clean ... just slighty dusty ... don't know i's been 20k miles

it's been 50's low and highs of 75-80 ... before it hit low 40's ... still i just think my car is old now

Vast majority of places DO NOT do the tire pressure inspection. They're in a rush to get the oils changed and get cars out of their. A little over or under inflation is acceptable by their standards because they know that they can easily avoid any blame for it. Best to check tire pressure on your own, and preferrably, when your tires are cold (meaning before you start driving in the morning) to get the most accurate measurement.

what kind of air filter would that be? The square ones for the stock airbox or a filter from a CAI? Either way, 20k is really pushing it. Even if it looks clean, pull it out and check the other side. If you have the stock filter, it's adviseable to replace it by now. If you have a CAI filter, it's best to clean it now. It's incredible how dirty the filter is at just over 10k miles. You'll know the difference after you clean it.

thanks for the advice ... i never pulled the filter out ... does it just pop out? i have the stock filter ... how much should i pay for a new one? my car is sluggish and jolts from 2nd to 4rth gear ... i've been thinking my tranny is slipping and when i have time i'll take it down ... i tried the injector cleaner and it helped a lil ... but i think it's dying ...

Why would you want to switch to Platinum when the stock plugs are iridium?

i've been getting an average of 28mpg on mix city/hwy driving ever since i got the car. i have 9500 miles on it n i switched to castrol syntec 5w-30 at 5000 miles and stil have same mileage

You need to check the tires yourself when they are cold. Ideally about twice a month. Even if they did bother to check them at Goober Lube the tires are hot from driving and the reading will indicate that. If they remove air the tires are underinflated, if they add they are overinflated.

On a different note, I just changed the air filter about 1000 miles ago (with a clean, new OEM filter) and have noticed better mileage - specifically about a 45-50 mile increase in overall miles driven on one tank (about a 12% increase in efficiency)

I can't remember EXACTLY what the stock airbox is like. Hehe... I've had my CAI for so long now. Anyway, if you've never replaced after 20,000 miles, chances are it is covered in disgusting crap. If I remember correctly, all you have to do is push out on the metal tab on the ... right???... side of the stock airbox. The top will loosen up and you can flip it off or take it off. The filter is the pleated square/rectangular piece that's right there. It SHOULD be white when brand new. I imagine your's is black. Haha. j/k about the black thing, but it will be pretty dirty for sure. I think most places advise replacing the air filter every 9000-12,000 miles (every 3rd or 4th oil change) or so. By then, the filter is pretty bad. They're not expensive at all if you just buy the regular Toyota filters. On the other hand, you can save yourself a little bit of money in the long run by purchasing a TRD or K&N air filter. They pay for themselves at about the 5th or 6th time you would have normally replaced your air filter because they are reusable. Some people fret over the K&N and TRD filters because of oiling issues. I still feel this is mainly the individual's fault for overoiling the filters when they take them out to clean them. The oil that is used to re-lubricate the filters takes quite a long time to spread over the whole filter. But some people are so impatient and they think they haven't oiled it enough so they re-oil with a second pass, only to realize that they overdid it. The K&N and TRD both run in the $50 range.

thanks for the advice again ... TRD for $50 sounds good ... i think i'll replace it

black ... the filter wasn't .. it was light brown / grey and the other side was dark brown and there was a twig in it ... about 3 inches long ... wow ...

well lately i've been getting 30mpg ... went up more than 2 miles/gallon for no reason ...
do those pen looking pressure gauges work?/accurate?

what should i get?

dang corollaAltis ... 28mpg since you got it ... maybe you had a dirty filter to start with? i noticed a difference after using injector cleaner at 15k miles but it went back to normal after 2 months

yah maybe i shuold check it. its in the shop to fix a sunroof rattle. its the second time in the shop for hte same reason but its covered by warranty. sux

Don't forget that many states require the gas pumps to use a certain blend of gasoline during the winter which has an effect on gas mileage.

Being that California is extremely anal when it comes to emmissions, you can bet that they're using it.

If you want a K&N filter, pretty much the same as a the TRD filter, I got one i'll let go for 40 plus shipping.