Engine Weird Fuel Economy on my car....

PCV stands for Positive Crankcase Ventilation. During combustion hot exhaust gas excapes into your crankcase, to prevent buildup the crankcase is ventilated to remove the gases. There's a little stopper inside that opens and shuts.

Here's a pic of one. They all look a little different, and attach to the engine differently.
http://macgp.clubgp.com/howto/pcv/pcv7-big.jpg

On the 1zzfe facing to the front of the car, it is on the right hand corner of the engine closer to the top. You may need to remove your plastic engine cover to see it. It has a vacuum tube pluged into it and fastened by a metal clamp. Use an adjustable wrench to get it off of there. Take the valve out, and blow into the end that was inside the engine, air should pass through easy. Blow through the side that sticks out of the engine and it should be hard to pass air through. If it looks brown and alot of residue is inside it, it's probably good to replace it.

My 02 corolla uses toyota PCV valve # 12204-22040.
There were two different PCV valves made for 2000, 01, and 02 Corollas.
I would take it to the dealership get them to check VIN# and check out the #'s on the PCV vavle itself. You may have to take the valve off to see the serial number, so bring a wrench. I don't know if parts stores have them yet, you can check.

It's easy to to.. just remove the hose from the end, unscrew the old PCV valve, screw in the new one, re attach the hose and your done!

maybe its just the winter, id waiting until it warms up and see if it gets better. i have a 93 and sometimes in the winter i drop to 18-20 MPG where i live.

i'm under warranty until next year. But i got my intake on so that would void my warranty if i take it to the dealer. My dads fuel economy completely dropped. He drives a 1999 Toyota Siena with 42k on it. He gets 200 miles on a tank. Thats 10mpg. He blames it on the winter time....

I get better gas mileage in the summer then in the winter when it get's cold. I'm getting about 270-300 miles per tank, but 20 mpg is just redicious.

well, i was in your same position, i was getting 18-22 mpg, city. i have a 97 corolla auto with 92k miles. heres what i did:
new plugs
new wires
new air filter
oil change and filter
new pcv valve
new oxygen sensor
seafoam in the intake
seafoam in the gas tank

i believe the seafoam is what did the trick, i felt power come back immediatly after flushing out the intake with it. also, the new oxygen sensor would help with fuel economy alot.
also, i got out all the worthless crap in my car, i had alot of junk wieghing it down.

yea I'll check into that stuff... I have a 98' corolla with 97K on it.... kinda weird too though man mine probably gets even less than 20 mpg I'd say like 10-15 TOPS I dk man it's weird I'll check the PVC valve this weekend since it's warming up again here in CO. Thanks for the help guys

another thing that might be a possibility is the type of gas with the winter mix. I just noticed as of last week that my gas mileage (half/half of city and highway is approx 27 mpg. I think that the gas stations took this winter mix out of the pumps which makes the gas mileage go down. I dont even know why they use this wintery mix? Also since the temperatures are going up too. Hey anyone know when toyota is going to go hydrogen lol.

haha I hope they do man we'd be gettin like 500 mpg lol

Ive seen that on alot of older cars. Mine doesnt do it, but Ive seen some where it will go from half to full in the course of a stoplight.

seafoam helped, i'm gettin 25-27 mpg city now. good stuff.

okay quick ? about that sea foam thingy..... where do u find it and how do u use it???

check out http://TRDforums.com/forum/showthread.php?t=1205

you put it through a vacuum line, like your pcv valve hose that goes into your throttlebody, and you can get it at Napa.

sweet thanks man I'll try that see if it gets better.

Couldn't you pour that in with the gas when you go fill up the tank?



I found out that i'm getting 35.4 mpg when I went to fill up on wednesday.

depending on where you put it, it'll clean different things. You'll clean your fuel injectors when you put it in with the gas. If you put it in the throttlebody, it'll clean lifters, etc.

I drive city/ hi mix. Consistently get 33.5-34mpg. I'm very throttle happy, so its not like I'm driving like grandpa. I calc everytime using my cell. The best I got was 44mpg mostly highway on a long trip. I laugh at suckers I work with who drive POS american trucks/suvs. I always tell them they are supporting terrorists with their gas money LOL.

that seafoam stuff is wonders....

http://TRDforums.com/forum/showthread.php?t=1952

Clean that MAF sensor. Its a pretty dramatic change.

I noticed some improvement in performance, but the gas mileage is still bad (now 18-20 city).

Okay, so today I finally took that o2 sensor out and replaced it (freakin $178 for the part at the dealer).

man, i gotta tell ya, the difference was almost night and day.
drove up to los angeles (from san diego) and back, i'm gettin about 36 mpg now, and the car's definately more responsive and accelerates better.

the old o2 sensor looked pretty crusty and nasty, a lot like the one vamp has on his DIY.

all you folks that are still having the poor gas mileage w/the 8th gens, check out your o2 sensor! (after you've done all the easier, cheaper things of course... like oil change, air filter, maf sensor cleaning, change spark plugs, pcv valve, etc).

I'm glad you got it figured out, but man, you could have gotten that part for like $50 from autozone or someplace.

-Doc

You can use seafoam but ther is one problem that I ahev experienced with my Honda,Volvo, and both the 98 and 01 Corolla. That is that the seafoam to too strong and can damage the fuel system. It's best if you only add abut 1/4 of the canister into your tank since the 98-02 corollas have a 10.8 gallon gas tank only a very few and rare corollas have the 13 gallon gas tank. To be honest this is what i do. I buy the Lucas fuel system cleaner (add all, about 3.48 at advance auto parts, small plastic bottle) and fill up on 89 yes thats 89 percent octane. Reason being is that is you put it too rich it may have pre-detonation and can possibly cause engine damage. Try this also, turn off your car, get a Q-Tip and some intake cleaner and soak the q-tip and lightly brush off the MAF sensor where there is a metal piece. It should have better flow and better idling.

10.8? I thought all of them had 13 gallon tanks.

(at least mine does and there ain't anything special about it)

Yeah I know my 98 Rolla LE had a 10.8 and my 01 Rolla S has 13 and my friends 01 LE also has a 10.8 so why are they like this I have no idea.

the worst gas mileage was 12 MPG and the best was 48 mpg on the 01 S the 98 LE consistently got 41 mpg . The 01 usually gets 35 city 40 Hwy.

man i'm getting angry.

gas mileage is back to being a crappy 20 mpg again.

Alright, I've replaced:

Air Filter (K&N)
MAF Sensor Cleaned
Spark Plugs replaced 4000 miles ago (brand new Denso Iridiums)
Replaced PCV Valve
Replaced tires/checked pressure (it was time anyway)
Oil change every 3k Miles (just did one yesterday too), Mobil 1 Syn. 5w30
Replaced 1st O2 Sensor with OEM Denso from Toyota

What am I missing??? What else could be the cause?
I'm just about ready to take this to a mechanic and get raped on cost.

Have you emissions checked and have a compression test. You may also need to see how much oil you are putting in. Check every time you fill up at least half a tank. and next time you add oil try 10w30 because at time higher heat can cause oil degredation which is breakdown of the oil and not lube the way its suppose to. if oil is leaking into your combustion chamber you may need to have them bored out and/or replaced with larger rings unless you plan to turbo it.

take your intake off completely (Take your time so you do not loose any parts) and clean with B-12 Chemtool or equivalent. Whatever you do Do Not spray into ports. Spray a lint free cloth and clean with that. If you spray into the ports you run the risk of oil coming off the cylinder walls and causing damage.

This should allow for better airflow and less restriction. Also have your catalytic converter.