Ask the Toyota mechanic!

I think plugs were replaced around 150k miles with denso iridium plugs, truck now has 198k on it. The plugs I replaced so far were denso iridium’s from auto one and the coils were replaced with denso.

I plan to replace the rest of the plugs as well.

I just thought it was strange that the cylinder misfires seem to jump around and it literally only does it when engine is cold and at WOT.

 

I wouldn't read to much into it. Replace the rest of the plugs and see how it goes. Don't throw out the Toyota coils. There's a good chance they are OK.

 

Mines makes the same noise under the same scenario (86k miles on truck). I also have a vibration at take off so maybe the driveshaft has an issue, just hoping it’s not in the trans.

 

Hope you can fix it. Does your transmission shift rough? I can definetly feel it from 1st to 2nd but otherwise it shifts pretty smooth. Its been like that for a while and even after I changed the transmission fluid at 60k

 

Just the 2-3 upshift is rough when trans is hot and WOT. All other shifts are good.

 

@Ruggybuggy Took down the drive shaft but the u joints were nice and flexible. Also the center support bearing spun freely. None of the parts had any play in them. Talked to my neighbor and his tundra does the exact same thing in the exact same scenario. Now its 3 trucks that I know do that. Should I still be worried about it? One other thing I've noticed is if I push the brake pedal all the way to the floor and start shifting drive and reverse, the sound is very minimal. Then I release the brake and start moving it makes like some groaning noises. Perhaps I should check the brakes and rotors next?

 

I posted this in its own thread, but it might get more traction here.

I dropped off my 2012 DC for some repairs. They're detailed in this thread https://www.tundras.com/threads/val...-bad-rear-shocks-to-boot.149190/#post-3736095

Now, the AC doesn't cool below 40 MPH. It's a bit intermittent when driving, but when I stop at a light, the temp from the vents starts towards the outside temp even with Max AC on. The recirc light is on, and seems to be working since the fan noise changes when I open and close it. I have remote start and I could start the truck, let it run a few minutes, and it would be cool when I opened the doors. Now it's still at outside temp. Does anyone have any ideas about what could have been damaged when they repaired the valley plate leak? I'll be taking it back for them to check on Monday, but it would be nice to have something to tell them besides "It's broke".

A little update, it appears that the compressor doesn't engage when the engine's idling. It did before the repair.

Thanks!

 

Resolved!

The mechanic didn't snap the low pressure switch back on properly. I'm not sure how speed affects things, but I'll leave that question to the philosophers for now.

 

No low pressure switch hooked up, no AC.

 

That's what I thought, but the fact that AC kicked in and started working at around 40 miles per hour had me confused. If there's no pressure in the system, it shouldn't work at any speed.

 

Without the low pressure switch connected the compressor clutch won’t engage. It’s designed to protect the compressor. No pressure means no lubrication.

 

Agreed, but so far no one's been able to explain why the compressor engages at around 40 mph even with the switch disconnected.

 

How do you know the compressor is engaging at 40mph?

 

The AC was blowing warm air until I hit somewhere around 40. At 50, the air coming through the vents dropped to 40 degrees. When I stopped to idle in traffic or at a light, the temp from the vents started climbing. The outside temp was around 80, and nothing except the AC compressor will drive the vent temperature that low except the AC system when the compressor is engaged.

 

Just reaching but maybe the tech was BSin you and it wasn’t the low pressure cut off switch. That all I got.

 

It was, I posted this on several forums and someone responded that they had the same problem on a Silverado when the switch failed. I raised the hood and found the loose connector. It's worked flawlessly since I plugged it back in. Since it will happen on two different manufacturers, my guess is that it's some obscure Federal requirement. A friend worked for GM back in the 80's and GM submitted a design for approval that would stutter the engine if the low oil pressure light came on. The Feds wouldn't allow it, the engine had to keep operating normally. When the GM engineers asked if it was better to allow the engine to lock up and possibly cause a wreck, than to stutter the engine and allow the driver to pull over, the regulators said that it was. I never understood that logic either.

 

So is your Tundra now fixed or was it the Silverado?

 

The Tundra's fixed. The Silverado is also fixed, that's where the person that responded to me found out that the low pressure switch would cause the AC to act that way.

 

Hi everyone,
2016 Tundra 5.7L 70K miles
Let me say, first of all, I love my truck. However, it appears that it has been possessed by evil forces.
I'm battling a recent big jump in fuel usage. Consumption has gone from an average 15 mpg (17hwy/12city) since new to an average of 9 mpg. Yikes! Driving habits and load have not changed. I been working on this for about 4 months and have checked/replaced all the obvious culprits:

New WIX Air filter
Tire pressures
Vacuum smoke tested (so tight it holds pressure)
OBD analysis of STFT, LTFT, air flow etc. appeared normal
New rear shocks
New tires (lower RR)
Checked for brake drag / calipers all ok
Oil change (I know, just a CYA)
Spark plugs replaced (old plug gaps were a bit high with age)
Cleaned throttle body
MAF replaced
AFR sensor$ replaced
Injectors removed and professionally cleaned
One thing that seems strange is that after each engine component change I usually reset the ECU with a battery disconnect and initial mpg would be a reasonable number for the first 20 – 30 miles then get slowly worse.
(Possibly ECU might be compensating for STFT trim, perhaps with eventual higher LTFT set point?)

I have not been to a dealer as I live way out in the woods in the great white north. Any ideas on what else I should look into?

I am wondering if the Air Injection pumps can fail and be letting air into the induction side without dropping a code? Kinda like a vacuum leak.

Your help would be much appreciated!

Thanks!

 

If it is flex fuel check the alcohol percentage levels.

 

Great white north as in Canada? We don’t have flex fuel Tundras in Canada. Are you running stock? Why did you change the MAF and AFR sensors and did you use Toyota parts? Are you hand calculating your mpg?

I’m running the exact same truck and see 19mpg hwy and around town around 14-16.

 

Yes, maple syrup on my bacon. I didn't mention flex fuel. gas only. stock truck except for TRD dual exhaust added. converted my L/100km to mpg for our southern friends. MAF changed because it includes the air temp sensor which can effect the mixture and could be reacting slowly. AFR's because I had run out of options. All genuine Toyota parts. makes no sense as to what is wrong.. . guess I can take it to a dealer and hope for an answer. I am wondering if the ECU has an error in its code and needs a reflash.

 

Have you done a manual calculation? Fill the truck up, wait 30 seconds and run the pump until it clicks off once. Go for a 100km highway drive. Maintain a speed of 90-100kph without using your cruise and drive conservatively. Do the drive on a calm day and flat terrain. Travel 50kms and return back to the same pump retracing your trip. Fill your truck using the same pump, wait 30 seconds then fill until it clicks off. Record the number of litre you added to the tank and the actual kilometres you drove. Determine the kilometre by gps and your odometer.

This might all seem straight forward but you would be amazed how many people don’t know how to calculate mpg.

You have to verify that you actually have a problem. ECU reflash is done if there is an update available and it’s done to address a certain issue that the vehicle is having. I’ve never seen a reflash for better mpg.

You had also asked about the air injection and if it could effect you mpg. The air injection is basically just blowing air into the exhaust manifolds and won’t affect mpg.

 

Good to know about the air injection. I have done multiple manual mileage calcs on all the vehicles I have owned over the years before we had ECU's and these cool economy reminder/readouts just to know how much it would cost to travel. My dad used to keep a notebook in the old Buick he kept for towing our trailer and I was in charge of doing the math.
Thanks for your input regardless. I find it funny how many threads there are for "bad gas mileage" and so many answers about how their mileage is normal but few OP's that come back with a fix that they eventually found. Guess those trucks are still out there ... I'm thinking the only fix is to swap all the original old, but good, parts back in and sell the beast and replace it with a slightly newer one with the caveat that it pass my mileage test run. lol.

 

Do you have Techstream to monitor live data? You can look at the load value to determine proper MAF performance. Here is an article to help understand. It’s for Prius but still applies.

https://attachments.priuschat.com/a...6_2010_Toyota_Prius_Repair_Manual_-_P0101.pdf

 

Also forgot to ask. How many miles on the truck? It’s normal for high mileage vehicle to have lower mpg. If you perform a leak down test it will help determine the health of the motor.

 

Minor collision that cracked the grill and now I have a "pre- collision malfunction" notice on the dash. Will swapping out the grill remedy this or is there more to it?

 

If should but depends on where the crack is. If it’s through the sensor cover you can just buy the cover.

 

Just bought a 2011 Tundra 5.7 with 230k miles. Was expecting to deal with a few issues but ive one now I’m not sure what to do with. I’ve read a lot of threads mentioning the same lights and symptoms and none that mentioned the codes I got.

Yesterday - Noticed shifting points were off. 1st gear would either be quick and jerky or I would have to apply almost 3/4 throttle to get it up and going from a red light.

Today- Started up and got 4lo flashing, TSC and Check engine non flashing. I would say it went into limp mode because I only had gears 1-4 and reverse was non-existent, it felt like it was in reverse but not. I disconnected battery, all lights went away and drives perfect fine including reverse for the next 70+ miles and turning the truck off and on 2-3 times. I got to autozone and they pulled codes P0894, P2714 and C1201. Went to the mechanic shop made an appointment and drove home. Running perfectly the whole time. What are my options here? Hoping to avoid labor costs

 

Check the condition of your transmission fluid and the level. Do you have any leaks? P0894 can be caused by an incorrect trans fluid level. I would address this code first.