I get very bad gas milage.
12MPg, Driving good (I was testing the gas mileage)
I Recently Replaced These: (within the last 1 - 2 months)

Plugs
Wires
Cap
Rotor
MAF
EGR Valve
Alternator


Ok, My muffler has a *cut* in the bottem of it. (It was rusty and i pushed on it to see how bad it was and it make a cut/hole in it.
1 or 2 other places of my exhaust system leak.
Within the next couple months I am hoping on getting a cat-back.

Idle:
When it park it will kinda fluxuate (500 - 600 - 700) or (500-600) or (600-700)
When I go and stop at a stop sign idle likes to go down to 400~rpm and the lights dim.

I'm thinking Timing and Vacuum Leaks ?
I will try to browow a Timing light from my grandpa.
Whut is all involved with this/ how long should it take?

Also how do I check for Vacuum leaks?

Thanks

Ps. Could all this be contributing to my bad gas milage?
It's also around -5F here ( around -20 to -25C)

 

I'm having a problem similar to that, except that my car after started will die out unless I keep giving it gas, alot of gas. The RPM"s fluctuate below 1000 then slowly dies off, I am not sure what the problem is. Last week the car wouldn' start up at college, got the starter fixed, now it just dies out. It's killin me and I am not sure what the problem is.

 

TTT........

 

I've got the same exact problem....

exhaust leak, and a rough idle....I am also getting really crappy gas mileage....my EGR was also replaced recently..

let us know how you fix it

 

I might try to make a ALDL cable to hook up to my pc to try to pinpoint the problem if its sensors and stuff..
I dont know if it will work but anything is worth it...
Gas is about $3 a Gallon here.....87octane..
http://www.winaldl.webhop.net/

 

If it's a vacuum leak, the car shouldn't want to idle.. And yeah it'll tend to stall or drop down pretty bad when you're slowing down. Can't see vacuum attributing to bad gas mileage though.. Could be timing fluctuations.. To check your timing, disconnect the EST (Electronic Spark Timing) cable..it's a little pigtail..tan with a black stripe. It's probably gonna be on the passenger side, right near the condenser..real easy to find. Disconnect that, and mark a notch on the balancer with a little white nailpolish or something that'll show up in the timing light.. Connect the light to your battery and assuming it's an inductive pickup light, clip it on your #1 wire. Start the car and pull the trigger..the notch in the balancer should line up with a timing mark on the plate. Although I did this last night and mine read 10 1/2, and today it read 4 degrees... Don't ask..I don't know why. Runs fine though!

PS-How's your O2 sensor? Ever throw any SES lights? A bad O2 sensor will kill gas mileage..usually makes ya run rich and if it's very bad, it can make the car run nasty.

PPS-How's your fuel filter??

 

Changed fuel filter recently..
No idea about the 02 sensor but there are no codes.
Thats why I wanna hook my pc to my ecm using WINALDL so I can see what sensors are bad and to see if I am running rich...
Hopefully it'l tell me something..

 

I bet anything that it is a low vacuum, since you replaced those other parts that would cause a bad idle. I always had some rough idles until I replaced all of my deteriorating hoses with silicon. You may also want to check your PCV valve since that is usually related to bad idle when faulty.

 

Devian...where'd you get your silicone hose at? I've seen those ***** hose packs with like 3 different sizes at Autozone or DAP, I forget which, but I don't know if it has the right sizes or not..I need to do vacuum lines too. Most of mine look ok but I'm sure they're getting a little nasty..and some blue silicone hoses around the engine bay would make it look quite a bit prettier...

 

The orange ones I got from www.hosetechniques.com. I had to do some math conversion to see which size to get. I used 4mm for the 5/32 lines, and 6mm for the 7/32 lines. I used the 10mm hose from the blower to the intake manifold. The lime green ones were given to me free by a friend, which he got from hose techniques too, and the blue ones were taken from a totaled Honda. I like hose techniques because I can choose from a variety of colors, and order it by the foot. They also come in Universal kits too. It was an improvement over the originals. The rubber hoses weren't nearly as bad as the plastic lines. I wish GM had made them out of metal or steel so that they wouldn't break when you touched them.

 

So you needed 4, 6, and 10 mm hose? I'll have to see what's in those kits. They're a tad pricey, but it's great looking hose, so....

 

I'm happy with them, they are thicker too and they don't leave a black residue on your hands once you touch them. Don't quote me on the 10mm hose. These conversion factors work for sure and are pretty close.


5/32 = 4mm
7/32 = 6mm
5/16 = 8mm
7/32 = 10mm (not quite the same, but close enough)

I used 8mm hose for my radiator overflow hose.


Washer fluid hose is a bit smaller, like 3.2 or 3.5mm.

 

TTT

 

Wow..that is EXTREMELY helpful Dev. Thanks man. I'm gonna order some of that hose pretty soon... Just got my hands on some extra cash.. $500 from my grandparents for no apparent reason or condition except that I need to get a job where I make more than $100 a week...McDonalds isn't giving me hours. Lol...that's pretty damn fine with me!

 

Make sure read the sizes on your hoses carefully. You don't want to order the wrong size or get more of a size you don't want. I have a bit of spare silicon hose left, the lime green one, which I got for free. I also used the spare silicon as hose covers by slitting them down the side. They slide on so effortlessly. The hoses are really easy to put on, but kind of tough to pull off, which is kind of the point. I don't even have to use clamps. I use a couple on the larger hoses as a safety precaution. I used some spare 6mm hose and made a key chain. I can find my keys easy now.

 

>UPDATE
I fogot to add, When my car is cold (in the morning or after school) I will try to start it and it starts and idles real rough at 300-400rpm so I give it some gas so it goes up to the normal 'warming up' rmp range (1200-1500).
Wtf?

 

Something's definitely wrong with the idle... Definitely just makes me think vacuum. Any breaks or deterioration in your lines? Any of them disconnected? Buddy of mine left a vacuum line unplugged and his car didnt want to idle..kept falling to like 400 rpms or so until he hit the gas...when it went back to idle it'd fall back again.

 

>UPDATE - All my vacuum lines look fine.


Umm I browowed my grandpa's timing light.
My timing is way Retarded its 6Deg!!!!
It's gotta be ten right?

Ok I want to know if i did this right.
K, I hooked the pos and neg of the tiing light to the battery; then connected the end of the #1 plug wire to the other wire from the timing light.
I made a mark on the crank pully (thats whut it is right... I dont know much I am only 16 and got my license 2 months ago but I had my car for a YEar lol.) Ok made the mark on the pully at 10Deg. Then the 'notch' or 'indent' thingy on the pully I also marked that.
Then I started the car up and aimed the timing light at the marker. The timing light flashes. The marker 'indent thingy' was on 6-7deg.

Could this be the reason for bad gas mileage etc?

Oh btw, How do I adjust the timing... MY manual says loosen the distributer.... how do I do that I cant seem to find the bolt.. I took the cap off but no go..

Do I turn it Towards the firewall or away?


Should I maybe advance it a couple degree's?
Keep in mind I want good gas mileage, I am up in canada and its 79.9 a litter thats about 3 dollars US a gallon.

Thanks

EDIT> I ALSO DISCONNECTED THE TAN WIRE.

 

"Some un-obvious things causing bad mileage that I can think of: a TPS that fell out of adjustment, exhaust leak near the manifold/y-pipe connection, one bad spark plug wire, dying fuel pump. And the obvious, spark plugs, deposits on inside of distributor cap/rotor, misadjusted timing (has the 0 degree mark on the balancer slipped?), clogged fuel filter, clogged air filter, etc- basically, all the major tuneup parts."

TomP said this to me when I posted my gas-eating problems. So probably with the timing you have found the culprit.

 

6 degrees BTDC would definitely cause for some crappy running. After you adjust that to 10, reset the computer and hook up the EST connection (you did disconnect it when you checked the timing right?).

If the car still is idling and sucking gas, I would look at having the injectors serviced and/or replaced.

My 85 was doing the same thing last year. I replaced the same things you did. It turned out to be injectors in my case.