2000 Tundra, Issues with Idle and Shifting into D, R in cold weather

2000 Toyota Tundra, 4.8L V8, 4WD, 120k miles

I just moved from CA to Denver, CO. Have driven in cold mountains for years in CA with no problems, but having issues in Denver, CO (its quite a bit colder in Denver). My problem has happened the last two mornings, both nights temperature around 10 degrees F. Also worth noting, I've been running it in 4Hi most of the time here, including 75 mile drives into the mountains. My check engine light did come on right after I put in some new gas. Truck was driving fine. I thought this was because I hadn't screwed my gas cap on all of the way.

Based on my research I suspect I'm actually have two different problems related to the cold weather. Also, oil definitely needs to be changes (I'm at the shop right now).

Issue:
1a) When I start it in the morning it will die if I don't give it gas.
1b) Just a light push on the gas, which is usually enough for this truck, does not actually rev the engine. I have to push the gas down very far, maybe 2/3 of the way. Then it will idle
1c) Once I rev it for 30 seconds or so, it will idle on its own (in Park)
1d) I shift into D, but it wont move. Shift into R, it will go, but some times I have to shift into R twice. Note: I'm in 4Hi while starting it
1e) After I've got it to go in R, I can get into D
[Day 1: No issues after this point]
[Day 2: below issues persisted after getting it to go in D]
2a) Once in D, the idle forward seemed faster than normal, usually a crawl, now definitely moving forward
2b) When giving it gas to really drive I have to push the gas down about 2/3 of the way. Then it starts with some power, which is unfortunate since I'm driving in ice / snow.
2c) If I put it in Park or Neutral, then shift to either Drive or Reverse it shifts into these gears very hard. Then, to go forward I really have to push the gas 2/3 of the way to go.

I'm at the lube place now getting
-Oil Change
-Transmission Fluid Change
-Differential Fluid Change
-Coolant change
-Idle system flushed and changed

 

This could be several different issues. Have you checked the codes to see what the check engine light is showing?

 

NOOOOOO not ANOTHER person from CA moving to CO

But yes, you will need to check the CEL is on for before you start going on a wild goose chase. To me, it sounds like a MAF sensor issue but that's literally just guessing.

 

definitely sounds like two issues, one of which sounds like a locked up throttle control motor.


with the truck off, push the accelerator pedal all the wya to the floor a few times (at least 6-7). make sure it's all the way, there'll be quite a bit of resistance since the throttle motor isn't helping you.

then try and start the truck and see if that makes a difference.

 

Code said it was an Oxygen sensor problem. I believe this is the same code I used to get when I had a bad gas tank cover. I had them turn it off to see if it pops back on. I'm guessing I just didn't screw it on all the way as it was cold as hell outside when I was filling up.

 

O2 sensor problem doesn't mean much, which o2 sensor problem? The upstream o2 sensor is one of the most important sensors on the truck. Its what tells the ECU how much gas to give it. If that sensor is bad nothing else will run right.

Loose gas gas cap is evaporative emissions control system.

 

Which is why I see it sometimes referred to as the Air Fuel Ratio(A/F) Sensor ?

 

Indeed. That is what it controls.

Its why knowing the code is so important. The downstream ones just report emissions, you can drive forever with a bad one...but the upstream ones will ruin you life.

 

My fault for not including the code. It was P0161. I included the description I pulled off Google below.

The rear Oxygen Sensor is located in the exhaust system behind the catalytic converter(s). ... Code P0161 sets when the Powertrain Computer or PCM has determined that the Oxygen Sensor Heating Circuit is malfunctioning. This means that the Heating Circuit is using too little or too much electrical power.

 

Interesting. Leads me to believe you might have plugged Cats.

 

That would be a different code, catalytic converter functioning below threshold...heater circuit failure is bad wire or just a failed sensor. This sensor should not cause engine problems.

 

Yesterday I had by AT fluid changed and my ignition system flushed / cleaned (at a oil change place, not a mechanic). For what its worth, also had my differential fluids flushed.

Weather tells me it got down to 12 degrees F last night, and the previous nights it was 10 degrees F. C

I just went out and started the truck and it started up and shifted into gear just fine (both in 4Hi and in 2wd). I'll keep watching it and see if this pops back up. Not sure if it went away for good, or just slightly different conditions lead to a good start.

 

I had a similar issue last night. Started up my truck fine (01 4.7L)
And moved it across the street after work to smoke and talk story with my coworkers after a long day. Shut it off then decided to start it again so it would be warm inside when I was ready to leave. It was only 45degrees out by far not the coldest weather I’ve started it in. It hesitated to start. Almost like the battery was dead. But I gave it some gas and she fired up, not really idling she almost died but I gave her a hard rev and she idled after that. Following this thread

 

My truck was doing the same thing. If I started it and shut it off rather quickly, it would hard start or extended cranks to start the next time.

I searched around and found that cleaning the throttle body could be the culprit. Since cleaning it, I’ve had no issues. Something to do with the ECM losing 12v power and not knowing where to put the TPS sensor before it has a chance to warm up. If anything, it won’t hurt to clean it as regular maintenance.

 

Heard that. I’ll do that next. Swapped the fuel filter out today and got some new spark plugs just because I’ve had the truck for a year and don’t know when the previous owner did any maintenance on them. Figure it couldn’t hurt

 

How do you flush the ignition system at a fluids palace? They didn't actually charge you for that did they? The air is pretty thin where you are.

 

Update: So far truck has been running great with the ATF fluid changed (I think the problem was that this fluid was a little low, and that problem only reared its head in cold weather) and the fuel injection system flushed. Although, it hasn't been quite as cold, so that could have something to do with it.

I had the check engine light turned off when I had the ATF fluid changed, and the check engine light came back on. I ordered a reader so I can see if the code is still the same and will update when I have that info.