What have you done to your 1st gen Tundra today?

so po446 was the only code. Even after a reset? And there is zero chance you unhooked stuff and put it back wrong? Start checking resistance of sensors.

jelly the seal of the gascap.

 

Read the whole post. Code cleared, trim levels normal. Besides that, I know my cap is good. When I loosen it to fill up, it sucks in a big gasp of fresh air every time

 

No codes currently and cap is super good

 

I read the whole post. Now twice. No mention of the gas cap. It's where I would start. It's cheap and easy. It's also literally the first thing any google search results for p0446 will tell you and it's what my issue was.

Edit here the list:

• Missing fuel cap
• Defective Evaporative Vent Valve
• Defective or damaged fuel cap
• Distorted, damaged or cracked Fuel Tank Filler Neck
• Torn or punctured Evaporative system hose(s)
• Defective Fuel Tank Sending Unit gasket or seal
• Split or damaged Carbon Canister
• Defective or damaged fuel tank

 

Clean the maf.

 

Bad gascaps throw codes tho right? Honest question

 

Yes. My gascap threw p0446. Changed it and the code has been gone 3 months.

The TX emissions inspections do a suction test on the gascap

 

P0446 was my code that hasn't come back.

 

Yeah I know, I'm the typo king

How longs it been? Strang you're still getting bad mileage

 

And I'm not sure how the gas cap could cause bad MPG. Weird that the MPG issue is still a problem even after the code is gone.

 

Go be a hooligan for 10 mins and see if it comes back.

 

I'm always a hooligan. Average MPH on my 35 mile drive home was 89

 

And no my driving habits are not the issue here. (before anyone feels the need to point that out)

 

I'm not a mechanic or a scientist, but my guess is something to do with a pressurized system having a leak

 

average!? Jeezuz Russel.

 

ok you sold your soul here. Now we know you driving is the root of your problems. You're dragging all the power out of your little 2uz and its tired and needs some attention.

 

That is not my name Jerry

 

maybe think about giving it a bit of water/meth spray on the hills, or stoplights. 50/50 is fine, but depending on your humidity you can take it to 65/35.

 

Ho-Ly-Shit, that was a long day.. reinstalled everything, moment of truth came along and it fired up perfect, burped the radiator and it’s parked back in the driveway where she belongs. Tomorrow when I get to work I’ll wipe everything down and check for leaks at the end of the day. Wife is furious, one of the kids got sick so I had to take an hour break to carpet clean vomit off of her bedroom floor. That was fun. Then had to get uniforms ready for an inspection tomorrow. Good news is new coil packs are due to show up tomorrow!

Fuck cam seals that shit sucked. By far the most serious wrenching I’ve ever done. In a week or so(when she’s done being mad at me) I’ll give the engine bay the feather duster treatment. Cheers fellas

 

@RUSTYNUTS

The maf reading 100 g/s when cruising/coasting sounds like the culprit. Wiring in that area damaged?

Should be more like 30-60 depending on speed/rpm/load.




5-6 g/s is normal for idling or throttle closed coasting.



P0446 is probably unrelated to the mileage being crap.

 

My names Daryl Jenifer

 

I cleaned the MAF sensor, so unplugged and replugged and haven't driven it yet to see if it helped. I was pretty sure the 5-6 g/sec was good on the low side, but the 100+ isn't normal at any speed/rpm/load, is it? It only got that high when accelerating, but the fuel system going into open loop happens just after cutting throttle and coasting. IDK. I'll run the scanner on another drive and record or screenshot data, unless it fixed itself. thanx

 

I'm gonna blame the fuel filter so shifty can tell me im wrong.

 

I hope you got it sorted by T2S. I've still got a leaking front diff and skid plate issues. Hopefully they'll all be solved next week.

 

My evap won't complete it's drive cycle after 30 days of driving. I'm thinking gas cap, but no codes. Wonder if it's the gas I smell every time I fill up? I know I have a minor gas leak near the top of the tank.

 

It’s never the damn fuel filter!!!! What’s with you people?!?! Aaaarrrgghhhhh

 

If you do end up having to replace it, Hitachi is the OEM supplier.

Here's Heather's review on Scamazon. I ordered from there before I knew they were bad about fake parts. Would probably recommend RockAuto to be safe.

Review on Amazon: Toyota OEM Part made by Hitachi (2002 Tundra 4.7L) https://www.amazon.com/gp/aw/review/B004SJS8YY/R1MIFV2AOY18L5

 

My truck doesn't even have a fuel filter