Road trip sudden power loss :(

I’ve got a 2005 tundra and I was on the way to Kansas from St. Louis with a buddy. On the way down we stopped at numerous gas stations to fill up and empty the bladder. Getting on the highway I noticed the truck seemed to be noticeably down on power below ~3k rpm throughout the drive power would come back and power would go even struggling to climb minor grades at 80. Upon arrival to Kansas , I stopped and cleaned the MAF and the problem persists. Loss is not noticeable when cold but when warm the car is down so much power that it revs sluggishly in neutral. I have recently bought this truck and when I pulled the MAF to clean it had residue from what looked to be a misting of muddy water all in it. Gas mileage has dropped significantly also. Maybe a new MAF maybe a new throttle position sensor? Not too sure but there is no check engine light and I scanned it and there is no codes. Trucks got 260k and I’m not too sure what to do especially being so far from home.

 

Does it have a factory air filter or is it using a after market k&m filter?

 

It has a drop in AFE filter that the previous owner installed. I cleaned it in the pre trip maintainence. Wasn’t dirty. Let it dry fully. No oil used as specified on the filter.

 

These trucks hate aftermarket air filter

read this
https://www.tundras.com/threads/k-n-cold-air-intake-vs-oem-air-filter-box.138095/

 

It’s not a cold air intake though. Same factory airbox just a reusable filter. It’s been fine until about a week ago. Had this truck for about 6 months.

 

Could it be the battery?

 

How's the condition of you PCV ?

Not that this will fix the problem but just a reminder that when a major component such as a MAF is cleaned,, especially in that condition, it's best to follow up with unplugging the battery for about 10 min. The ECU will then go thru a relearn process....idle speed, throttle position, fuel trim....etc

 

I was thinking cats clogged. Is the exhaust system original

 

It's oiled filters that are the problem. Oil will coat everything downstream. If your filter is not oiled, no problem. But I will say: Toyota makes their OEM filters a bit less aggressive than aftermarket (fuel, air, oil) intentionally, it seems. I'm basing this info on various test videos I've seen where people do side-by-side filtration on each and offer up results. That said, I run all OEM. And that's coming from a hardcore Wix user. If Toyota says it's right for their engines to run a million miles, and it costs less than aftermarket where I source it (direct from Toyota), I'm all in.

Cats very rarely clog on the first gens. And when they do, you absolutely will get a code. But as many have found on here, 'cat inefficiency' codes often trace back to oxygen or air/fuel ratio sensors.

OP's issue sounds more like a bad coil pack or bad O2/AFR sensor.

 

Will it still drop gears if you throttle it but just accelerate like normal?

have you checked ALL your fluid levels?

an overheating engine will act like this as well.

 

I was wondering about this, I would think OP would be feeling/hearing the miss though.

Sometimes these trucks take a while to throw a misfire code. How long has it been doing it distance wise?

 

I thought that too, until I saw others on here who had the symptoms without the code.

 

Poor gas mileage is often O2 sensors. They don’t have to fail to start affecting the engines performance. That being said, yours sounds like it could be bad gas, or even old worn spark plugs if it struggle to gain rpms.

 

Driver would likely describe a misfire as a “shudder” rather than sluggish.

could be a lot of things… fuel pressure regulator is a possible cause.

but I’d start by ditching the oiled air filter for an OEM equivalent, re-clean MAF and disconnect the battery to reset learned trims.

 

OP states no oil for the filter, just cleaned

 

gotcha. Never seen a serviceable air filter that was not oiled.

Also, re-read and saw that car runs better cold than hot.

Could indicate it is leaning out as it warms up… low coolant temp enriches base fuel map.

again, could be a number of issues from fuel delivery to an air leak.

 

As others have said, it could be a lot of issues. Sorting through something without codes isn't fun, so I feel for you.

If the MAF was all clogged with a "misting of muddy water," I'd make sure to look at your throttle body as well, and clean it out really nicely.

I dealt with a faulty fuel pump for a while, which presented itself as an ever so slight stutter under acceleration. Not saying that is your issue, but a fuel delivery issue wouldn't be out of the question, if everything is clean on the air intake side. Speaking of which, you could also do a quick check for vacuum leaks, which could also be a culprit.

Did you check the TPS opening percentage with the key in the "on" position? Should be around like 13 to 16 or something.

Edit: Adding a question...What RPMs are you idling at in neutral and all accessories turned off?

 

K&N owns AEM.
AEM makes a dry version of their filter.

 

When it was down on power, did the engine bog when you gave it gas?

I had a bad coil pack with this issue. No codes until 4 days later. Changed one coil and it was good to go.

 

Not on the 1st gen w/4.7L, historically speaking, from several cases. Normally I'd agree, but we've seen it too many times. One of many cases right above my comment here, I can likely dig up some of the others from the past on here if you don't believe it.

 

PCV is original with the truck, I ought to give it a look

 

this MIGHT be a possibility but it is on and off id assume a clogged cat would be consistent.

 

yes I have an Ultragauge and I had my eye on the temperature the whole time never went over 191f hovered around 185f consistently.

 

Round trip ended up being 900 miles, but I identified an issue about 100 miles in.

 

id taken the whole intake tube once id seen the mess on the maf.
ill keep the vacuum in mind, I have not tried to check for leaks yet
have not checked the tps with key on but I'm certain my ultragauge can do it.
600- 700 rpm at idle with almost 0 load.

 

Is this on your 03 w/110K in your profile or you also have this 05 ?

....and throw codes.

As for PCV....pucker up or simply replace it if over 100K miles.

 

I put new plugs in it less than 10k miles ago so I doubt that's an issue. when looking at the o2 voltages upstream and downstream stay a similar distance apart but looking at the voltages between the left and right bank, Bank 1 sensors have a consistently higher voltage than a bank 2. Just glancing at o2 voltages I remember them also being completely the same between the right and left bank so this makes me wonder if there Is incomplete combustion somewhere causing the higher 02 voltage. checked long and short fuel trims and they are all the same so somehow there is extra fuel getting through or the sensor is at fault

 

Where’d you get the plugs? There are counterfeits abound. Someone recently pulled a plug out that was almost disintegrated and misfiring.

 

My buddy's son was selling a pristine 05 v8 4x4 crew cab sr5 in blue for a STEAL. It has got around 235k and no rust (besides under the evaporator drain). all was swell until I left for the road trip, now its got v6 power AND v10 gas mileage

 

if I'm not mistaken I bought Denso plugs from Rock Auto, so I doubt they'd be fake. Although that's still entirely possible