Really Needing Advice

Hello everyone,

I have been experiencing what seems like lots of things happening at one time with my 2010 4x4 4.0L Tacoma with 120k miles and looking for possible things to check or have checked.

Here it goes…

I’ve noticed a week ago that my truck hesitated to crank up after work one day and shortly after this, I noticed that I filled up at the gas station and I religiously check my mileage and reset my trip after each fill up. My gas gauge dropped from full to around 1/8 from full after going 10 miles which I thought was really odd and was thinking maybe there was something up with the fuel pump? I also was driving uphill on dirt road. And I have not seen anything leaking.

Another thing I’ve noticed for a few months now is a shuddering in gear at idling and acceleration from stop. Mostly around 1500 rpm and around 15mph and really noticeable on an incline. I am having both wheel bearing hub assemblies changed on Friday. I was told possibly motor mounts also? Any way I could check this or any other things to check?

Oil and filter were changed about 3k miles ago as well has transmission fluid change, diff fluids, transfer case fluids. I also had new tires installed about 3k miles ago.

I saw information on here about MAF and o2 sensors… is there a way to check these if they need replacing?

Thank you for any advice you can provide.. would really just appreciate any direction for what to do.

 

Here are some thoughts.
For the fuel issue, the first thing I'd try is a bottle of Techron and you can get it at almost any store that sells automotive chemicals. You may have gotten some bad fuel. If that doesn't help, I would get my fuel pressure tested you may have a fuel pump failing. Regarding the fuel gauge issue, I'm not sure but may be related to the fuel issue. I don't know if the gauge still works off of a resistor element or if they've come up with some new and improved technology to register fuel levels. Haven't had to look at one in years.
For the MAF and O2 you may see a code. You can purchase MAF cleaner, again at most stores that sell auto chemicals and it is fairly easy to clean. Two screws to remove, lift it out and spray it down, clean. I don't even think you need to disconnect the harness and it's on the top right side near the air cleaner. Just be careful not to damage it. The O2??

 

I would PERSONALLY think that if a MAF or O2 was bad enough to CAUSE an mpg drop like that, you would be getting codes, but I'm no pro and at my age, have no inkling of playing one on TV.

 

Check u joints and battery.

fuel not sure what tests can be done. Did MAF and TB clean, O2 sensors, fan clutch, FPR.

Serviceable URD pump looks better than stock. Don’t know how many miles left on my factory pump. Most car LPFP’s don’t last this long.

 

Would a code come through for a fuel pump issue? All u-joints were replaced in November. I was told at the time that the shudder was from uneven tire wear but seems to still be doing it even after new ones… would bad ball joints cause any of these symptoms?

 

What is TB and LPFP? Thank you.

 

Throttle Body, Low Pressure Fuel Pump.

 

The shudder. Is this automatic? Could this be the torque converter, lockup shudder? My understanding the test for this is to drive up to speed of the shudder and slightly apply the brakes and if it disappears, it's the torque converter trying to lock up.
The fix for this is to add a tube of

$15 Lubegard 19610 Dr. Tranny Instant Shudder Fixx 2 Ounce 2 Pack

Lubegard 19610 Instant Shudder Fix. (Amazon)

 

Drive it in “4” if the shudder goes away it’s your converter. It usually happens under lighter throttle. Lubeguard will work for a while but it will come back.

 

Update:

Took it into a shop today and they think that there is something going on in the real differential and that it didn’t shudder in 4wd. I had my u joints replaced in November and no leaks that they saw. Are differential problems common? What are some things I could check if any?

 

yes it’s automatic

 

If you have a GoPro (or can borrow one) it's a great diagnostic tool for finding loose parts. Try to film during daylight at a high frame rate. When they do the bearings have them rotate the tires. Check battery voltage, low voltage will make these trucks do weird shit.

 

Check the bearing that holds the middle of the rear driveshaft. Those go bad and can cause some vibes.

 

center support bearing was replaced back in November

 

The "Tacoma Shudder" can be a lot of things and tricky to diagnose, but in your case, I would start at the transmission, especially if problems occurred shortly after the service. Do you know what fluid was used in the transmission service? Make sure whoever did it, filled it with the proper fluid (Toyota/Aisin WS or equivalent) to the proper level. Lube Guard also works wonders but will mask a torque converter issue, which could be a likely culprit, especially if it disappears in 4WD.

If you're running stock-ish size tires and not abusing your truck in the rocks or beating on it in the desert, Toyota differententials are pretty robust. I guess you can't rule out the rear diff so I'd make sure the rear diff is at the proper fluid level and move on to something else.

If fluid levels check out, an easy thing to try is flipping the center support/carrier bearing brackets. After trying everything else on my wife's 2006 with similar symptoms, flipping the carrier bearing bracket solved the issue. Super easy. Just un-do the 14mm bolts at the carrier bearing, lower it slightly, spin the bearing brackets to flip their orientation and re-install the 14mm bolts, tightening to Gudentite. Go for a drive and see if your shudder is gone.

Toyota had a re-call on rear leaf springs of various years, if not all 2nd gens, but it's been a while so I'm a little fuzzy on those details. You can scan your VIN on Toyota's site and make sure whoever owned the truck before you had the leaf springs replaced under the recall. A broken or badly worn set of springs can cause shudder issues like you described.

My hunch would say your fuel issue is unrelated but can't rule that out from here.

Good luck and keep us posted!

 

This 100x. Skip the snake oil additives. If you are at all mechanically inclined read up on the fluid check procedure on here and do that. Unfortunately its common for shops to underfill these trucks. Theres a very specific procedure that has to be done with the truck running to get an accurate level reading

As for the gas consumption. Id continue to monitor this tank and do the math to get the true mileage next fill-up. You mentioned some off road uphill driving which will naturally be lower MPGs

MAF and throttle body cleaning can certainly help

Lastly, rear diff issues are uncommon on these 2nd gen trucks.

 

I serviced the transmission myself with Valvoline ATF in the red containers and changed the filter. I used the trick that was posted on here to check levels with A/T Temp illuminated light and seemed to do what it was supposed to.

I believe diff fluid calls for 75-85 gear oil but I couldn’t find any in my town so I looked at these forums and saw that 75-90 would be acceptable. Mobile 1 is the brand I used.

I did take it to a shop to diagnose a humming around 60MPG it turned out to be wear bearing according to the shop and I had both replaced and the humming is still there so IDK about that either… while I was there, they told me that my leaf springs were really loose.. could the leafs be a potential cause for the vibration?

My plan is to change get a tire balance and rotation, change oil, spark plugs, clean MAF and throttle body this weekend to see if there are any differences.

As far as carrier bearing, after loosening the bolts, the bracket should be able to flip around?

 

I have never heard of a rear differential being bad under regular/normal driving conditions. And I have never heard of torque converters being a problem.. what kind of job does that entail? Is it common in 2nd gens?

 

No not really

Are you sure you did the level check procedure correct? Truck running, parked on level surface, fluid at the correct temp, and you the pulled the CHECK plug until there was just a trickle? The check plug has the small 5m hex key, not the regular hex head bolt.

Im just confirming as this is an extremely common issue and a big source of errors - not insulting you.

Assuming all that is good its possible the CB was installed backwards and has failed early. But shuddering while idling / not moving rules out anything related to drivetrain like the carrier bearing, hubs, or needle bearing

If you have an OBDII reader with live data you can monitor various values such as O2, MAF, and fuel trims if you wanted to.

 

I am positive. Pulled check plug until trickle while truck was cranked and no leaks that I have been able to notice since then. I’ve had this little shudder before I even changed the transmission fluid and that was back in September or October when I first noticed it…did not seem as prominent then as it is now. But originally I noticed the shudder and then started hearing and feeling the effects of the carrier bearing