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View Full Version : Gas Milage took a dive!?


Big-J
05-10-2010, 10:12 AM
Lately I have notcied my milage is terrible, and the idle is fluctuating.
I replaced my O2 sensor not too long ago, and it seems like it started after that. Any ideas on what is causing this?

Thanks for you help!

nakman
05-10-2010, 10:27 AM
For a choppy idle I'd hunt for a vacuum leak, and/or leak to the air intake. Also did you disconnect the battery for a while to reset things after you replaced the O2 sensor?

What kind of truck? maybe it doesn't matter... the above guess is universal.

TIMZTOY
05-10-2010, 10:33 AM
Mass air flow , or map depending on car. Also check the easy stuff.

Slarkplugs. Fuelfilter. Airfilter. Timing.

Big-J
05-10-2010, 12:12 PM
I didn't dissconnect the battery after I replace the sensor, I'll do that today when I get home. I check for leaks, but my plugs should still be good, I replaced them not too long ago.
Not sure how to check the timing?

Its a 99 4Runner SR5 btw

nakman
05-10-2010, 05:10 PM
You could have just got a bad tank of gas, it happens. Look for any cracks in the big air tube going from the air filter to the intake, squirt something highly flammable at it while idling, see if anything changes.

Also check out the "routine maintenance brings the suck.." thread, for some nicely detailed pictures of your engine being taken apart and put back together. Maybe something will look different and jump out.. :confused:

TIMZTOY
05-10-2010, 11:54 PM
clean your mas air flow sensor, if it dosent fix it, it should be done regularry and will help anyways.. but use only mas air flow cleaner.. NOT brake clean your timing should be fine unless your timing belt is stretching..

Big-J
06-02-2010, 10:26 AM
Thanks for the tips, I had to go out of town for and have been so busy I haven't had time to take a look. This weekend I will clean my mass air flow sensor, I replaced that last year Im pretty sure.

I will try out all of everyones suggestions, but if all else fails, anyone know of a place that isn't going to charge me a lot of doe just to figure out what the problem is? Do you think a diagnostic would find the problem?

Thanks again for all you input.

timmbuck2
06-02-2010, 10:39 AM
squirt something highly flammable at it

:lmao:

nakman
06-02-2010, 11:00 AM
:lmao:

hey man, it's free advice... you get what you pay for! :hill:

Big-J as for paying someone, check out the vendor section here. I think ATLR is a pretty good 3.4 guy from what I've heard http://www.risingsun4x4club.org/forum2/showthread.php?t=8747, Robbie is pretty much an expert at everything http://www.risingsun4x4club.org/forum2/showthread.php?t=10843 and you would be in good hands at Sleeoffroad (http://www.sleeoffroad.com)as well. hth!

Big-J
06-02-2010, 11:40 AM
hey man, it's free advice... you get what you pay for!

Ha! You wanna come show me that trick, I learn better from watching someone do it first......I stand way back! :thumb: :D

ttubb
06-02-2010, 12:02 PM
Are you running a K&N air filter or other non-stock filter that requires oil? That can cause MAF problems for sure, I speak from experience. T

Big-J
06-02-2010, 12:36 PM
Are you running a K&N air filter or other non-stock filter that requires oil? That can cause MAF problems for sure, I speak from experience. T

I am actually, the MAF is the first thing Im going to check.

The thing I notice most is the idle, it dips down to about 1k and starts to shake a little.

Big-J
06-04-2010, 11:07 AM
Ha! Now my starter went out. :( Good thing its not all that hard to swap, but not how I wanted to spend $100.

nakman
06-04-2010, 11:21 AM
Ha! Now my starter went out. :( Good thing its not all that hard to swap, but not how I wanted to spend $100.

Don't spend $100! Odds are very good it's just the contacts, which is a $20 job for both the contacts and the plunger. Hardest part is getting the starter off, it's a downhill job from there. Plenty of threads abound for how to do it.. and every dealer stocks the parts and should know what you're talking about when you call.

Big-J
06-04-2010, 01:00 PM
Too late, already bought the stupid thing! I can always take it back though.
Can you link a thread?

nakman
06-04-2010, 01:55 PM
Too late, already bought the stupid thing! I can always take it back though.
Can you link a thread?

See page 2 of this thread... http://www.risingsun4x4club.org/forum2/showthread.php?t=8913 forget for a moment that it's on a 80, it's essentially the same job except for the location of the starter, and the part numbers on the 3.4 are probably different. I've done them both though, once the starter's in your hand it should be pretty obvious what's up.

you could probably search yotatech for "starter contact" for more 3.4-specific pictures, as I don't know that this has ever been documented here.

edit: few more 80 pictures http://www.risingsun4x4club.org/forum2/showthread.php?t=11158

corsair23
06-04-2010, 02:01 PM
Can you link a thread?

Here is the write up I used when I did my first rebuild...I'm a noob when it comes to wrenching and this helped a lot...

http://www.george4wd.taskled.com/starter.html

The most important part of this job is getting the new contacts flush and "square" on install. I'm 1 for 3 on that score :rolleyes: - I rebuilt the starter in my LX once and no problems in 3 years. I've rebuilt the starter twice in my 80 and each time the rebuild lasted under a year :o - Third time I took it to an expert who cleaned up my relatively "new" contacts and plunger and did it right :hill: - Best money I've spent in a long time because the :Princess: was tired of having to smack the starter in parking lots.

EDIT: Tim's faster than me :)

Big-J
06-04-2010, 02:01 PM
Thanks nakman, but i think I figured it out. Leaving work early today to get this taken care of before tonight, I have to give a friend a ride to DIA!

Mountain States has the contacts, I just have to take it in and see which ones I need. I guess they can brush the copper in the plunge and Im good to go! Then Im off to return the new started I picked up last night.

Really glad I posted up, now I can buy more beer this weekend! :beer:

Big-J
06-04-2010, 04:33 PM
So it turns out I can't do it myself, the starter is in a bad spot where I can't get to it with the tools I have, + I don't have stands.
Can anyone recamment a place that can take care of this for me? Im going to have to have it towed, so somewhere closish to the downtown area. Mountains States wants $250, which I really don't wanna spend that much.
Im pretty much stranded without my 4Runner and need this taken care of quick, your help is greatly appreciated!!!


Its a 99SR5, V6, 4X4

nakman
06-04-2010, 04:48 PM
So if you have an SR5 is that a 5-speed? If so just roll start it for a while.. if not you can typically get a few more starts by just smacking the starter with something- like the end of your longest socket extension, or the handle of an axe, or whatever you can poke down in there. You don't even need to hit it that hard usually.

I can't think of a shop downtown, I'm sure someone else will.

Big-J
06-04-2010, 05:04 PM
It's an automatic, so the whole roll start won't work for me. I'll have to try and hit it and see what happens though, otherwise Im going to have to have it towed.

Either way I need to get it fixed ASAP! I called Robbie and he is out of town till next week, I wasn't too excited about ATLR when I called them last time, calling around now for pricing.

corsair23
06-04-2010, 06:28 PM
Can anyone recamment a place that can take care of this for me?

Sent you a PM...Good luck and hope it helps!