2004 Toyota Tundra V-8 Pick-Up with Random Misfire

I read the following message thread in its entirety, but since my problem is with a basically "new" first-generation Tundra, I am hoping that it does not involve the more serious post-maintenance electronics and related issues discussed here:

https://www.tundras.com/threads/multiple-cylinder-misfire.128826/#post-3290119

2004 Toyota Tundra V-8 Pick-Up with Random Misfire

I have a 2004 Toyota Tundra "SR5" V-8 pick-up with *very* low mileage, and during the last 800 or so miles it has developed a pronounced miss at idle. When the engine is revved to around 1,500 RPM, it seems to smooth out. The miss is not detectable at cruise speed.

If the engine is cold, it takes about a full minute for this problem to manifest.

I spent a couple hundred dollars at the Toyota dealership where I bought the truck, where they trouble-shot the engine with their high-dollar analyzer equipment, resulting in the mechanic announcing that the miss was moving from cylinder to cylinder. (The Check Engine light had never illuminated at this point, nor had it ever appeared since the truck was new.) They concluded that something about the fuel was the likely cause of the problem, and thus they sold me an expensive bottle of fuel additive.

I waited until the fuel quantity was well below half, poured in all of the additive, and then drove the truck until the quantity was around one-eighth full. I then topped the tank with non-ethanol Premium fuel, and have kept it topped with that fuel ever since.

However, the engine's rough-idle behavior has not changed since then - if anything, it *may* be getting worse - but during that interim the Check Engine light has illuminated twice. The first-time was code "P0303" - "Random misfire on cylinder 3" - and the second was "P0301," referring to cylinder 1.

I am reluctant to take the truck to another shop, without a good idea of what's going on - and how to address it. The last thing I need is for a mechanic to spend a couple or more expensive hours on it, and then tell me: "Well, you have a random misfire that is moving from cylinder to cylinder." Duh!

(If it matters, the elevation here ranges from 1,000 feet MSL to 1,500 feet.)

FWIIW, one mechanic I've known for a *very* long time theorized that if the roughness is happening only at idle, then there *could* be an issue with the throttle position sensor. Comments?

Another very experienced mechanic said that the truck had been sitting too long between periods of being driven, which caused the injectors to becoming fouled with old fuel. He recommended adding "Sea Foam" or similar product to every tank-full of fuel, for at least the next 1,000 miles or more. (He said premium, non-ethanol fuel wouldn't make any difference.) How likely is this to cure the problem?

Has anyone else encountered this behavior, and if so, how were you able to fix it - if indeed you *were* able to fix it?

Thank you and best regards, MarkT

 

Maybe try swapping the misfire coil from 1 bank to the other bank. It's a free troubleshooting practice to rule out the engine, or the cylinder. If it changes with the coil, then it's a bad coil. If it's jumping around look for an electrical issue, maybe a ground point somewhere along the engine block and battery points. I had a misfire with an 07 5.7l, it's a different platform in a way, but my misfire was resolved by finding the lose ground. The last option may be a rodent chewed up something electrical somewhere.

 

Hi ! You just posted on my thread, I just came across a different bit of information that says "misfire at idle, moves to different cylinders". On that '04 Sequoia they changed the crank sensor. I'd recommend using a Denso part, I'm going to try that on my truck.

 

Thank you blackdemon and No Neck Shrek. The way the truck has always been securely housed, rodent or insect damage is unlikely. As to coils, I'll try your recommended swapping, and use Denso if replacement is required. In the meantime I will continue to run it with the fuel additive, and see if the behavior improves. Best regards, MarkT

 

First off, obligatory "Low mile is not necessarily a good thing with 1st gens, it can actually be really bad."

For example... timing belt is supposed to be changed ever 9yr/90k miles per Toyota on the 2UZ-FE, though you can fudge that a couple years and 10ks of miles. Rubber tends to dry and crack with non-use, same reason these trucks in low-mile format like mine have absurd valve cover gasket leaks. All it would take is a dry belt to jump a single tooth and it'd cause you misfires, which may be randomized in the way you described. It's an interference engine, timing belt failure can be catastrophic.

Would like more info.

What is the exact code/codes currently logged indicating misfire?

How many miles, exactly?

How long did it sit idle, unused?

What's the maintenance history? Anything that would require disturbing fuel rail, throttle body/assembly, or intake manifold?

Have you done any maintenance to parts that have a bearing on EFI operations, like ... if the truck wasn't driven in 5 years and just sat at grandpa's house because he passed, did anyone bother cleaning the MAF, which is critical to EFI operation, because it notifies the ECU how much air is incoming, so it knows how much fuel to spray for proper a/f so it doesn't misfire?

Have you attempted the basic steps of swapping the coil pack and spark plug from the misfiring cylinder to an adjacent cylinder to see if the misfire follows?

Did the previous owner(s) make short-trip drives or ??

Was it in a rust-belt state, or somewhere without salted roads?

I'm sure I could ask more but this is a lot already. Help us help you. Give some concrete details and history here so we're not plucking at straws.

 

Thank you for the comments and questions, Shifty. My apologies for being less specific than I had intended to be, but somehow I fat-fingered the keyboard and accidentally sent an earlier draft of my first posting to the forum.

In any case, here are some of the details I *intended* to post intitially, with answers to your questions following:

Mine is a 2004 Tundra "SR5 iFORCE" V-8 two-WD half-cab, with slightly less than 3,700 total miles.

The Check Engine light has illuminated twice [only]: The first code was P0303, "Random misfire on cylinder 3," and the second was P0301. There are *no* codes showing currently.

Other than a mandatory factory passenger-side air bag recall, and a single session of dealership roughness troubleshooting, the only service to the truck has been periodic full-service oil changes.

I have tried to drive it on 25- to 75-mile trips monthly, doing almost no local driving, and the longest it has sat idle at any one time has been around five months. It has *never* been driven on anything but dry, salt-free paved roads.

To this point the coil packs have never been swapped - unless the dealership did so during that single troubleshooting session. Due to a rotten lower back, I'll likely have to take it to my local (long-time) mechanic to do any coil or similar parts swapping.

Rodent or insect damage is pretty much out of the question, given the secure 100% garage protection it's always enjoyed. Thank you, MarkT

 

Were you missing a digit in that mileage, it has less than 4k miles total? Or was there a missing 1 at the beginning of that, i.e. 13,700k miles?

Misfires on EFI engines are always either air/fuel/spark related. Problem with air metering (i.e. MAF giving bad info), air delivery (air reaching the engine, obstructions) fuel delivery (amount sprayed in), a/f mixture (no outside leaks in manifold or leak in fuel), or spark (weak spark, bad ground, bad coil packs), and even potentially a/f monitoring by way of O2 sensors potentially malfunctioning and sending bad feedback to the ECU. Any one of those things being 'off' can result in a misfire. Hell, even bad power delivery, i.e. a bad/weak battery or corrosion inside the batt cables can cause this.

On a car with THAT low of miles, I doubt it's the electrics, quite frankly, so I wouldn't go there, the OEM electronics on these trucks are light years better than store bought crap and will last 250k-350k miles. Nut if it sits for long periods, tired battery or corrosion at the post, or inside the cable sheaths could be it. In cases where only one cylinder is persistently throwing the error, you can typically just toss the plug and coil pack from that cylinder into the adjacent cylinder and see if the code follows. If not, you can try the same with the fuel injector. If it doesn't follow, chance are it's not fuel or ignition.

But really...

Regardless where the low mileage, you're sorely, sorely overdue on your timing belt change on age, at double what Toyota recommends (every 9yr or 90k miles), and the 4.7L is an interference engine, so I wouldn't take it lightly. Things tend to freeze up and dry up over time, and who knows, maybe you skipped a tooth. I'd highly recommend going out and buying the OEM-supplier's (Aisin) water pump and timing belt kit (this one) but NOT from scAmazon or fleaBay because some here have gotten knockoffs from those sources, and at least one person posted pics of a super suspicious looking water pump in the otherwise normal-looking box kit bought from scAmazon recently.

While I realize this doesn't answer your question about "what's causing this", and it's not an inexpensive job, it *WILL* force the mechanic doing the work to confirm the timing is accurate. If timing is off slightly, you're killing two birds with one stone, the belt replacement should have you back in order again. If not ... time to get crackin' on checking the other stuff.

I hope you've also been changing the oil once a year, just to avoid varnish in the heads. Gah, as a fellow low-miler, I wish my previous owner and a few other previous owners would've listened to the experts on that one ...

 

Although very different, the problem could still be related. I have a high-ish mileage '02 Accord that had the same kind of random/switching cylinders misfire. My problem were old plugs that should have been replaced long ago. Your plugs could be corroded/fouled from lack of use. Pull a couple and see how they look. New set of plugs solved my misfire issues. Runs like a top now.

 

Thanks, Shifty! Yes, the mileage is just under 3,700 *total* (that's *not* the reading of one of the two trip meters, as the dealer first surmised), and the high-quality main ship's battery is less than a year old. I'll check with my mechanic about installing the Aisin kit, and in the meantime will continue to evaluate the intermittent miss. Stay tuned, MarkT

 

Thank you, Baller! Good idea to check those plugs. Stay tuned, MarkT

 

3700 miles. Wow. Troubles at idle are often air delivery related. MAF, IACV and the more common issue, vacuum leaks. Spark plugs can also be suspect. I would also be concerned with the fuel injectors potentially being clogged due to varnishing from lack of use.

 

Thanks, Knabores. Per my original narrative, both the Toyota dealer and a very experienced local mechanic pointed to possible injector fouling. Both recommended an appropriate fuel additive, the latter saying to use it for at least 1,000 miles.

I am currently using it, and will continue to report back. MarkT

 

If I was in your shoes, I'd cut my losses and sell it.
Please let me know if you're interested

 

Well BubbaW, what's it worth? It is absolutely *pristine*, inside and out.

In the meantime, the body size of this one is just perfect for my needs. The newer ones are huge *monsters*, and I want no part of those. MarkT

 

Saw this little tidbit and thought I'd respond.

That is normal and has to do with open loop vs closed loop.

In Open loop the ECU is not relying on certain sensors for fuel management/emission control which results in a rich condition, higher idle, etc until the ECU reaches a predetermined coolant temp

In Closed loop the ECU uses pertinent sensors and in particular A/F sensors as feedback for fuel control.

 

It's worth whatever the MSRP shows on your sticker and then some if you sell it the right way. $30k plus is what they've been going for on Bring a Trailer if I remember right.

What's the story on this truck? Post up some pics we'd love to see it.

 

Thank you, BubbaW. The initial roughness may have to do with the ECU, but it persists at idle, even when the engine is at full operating temperature. At stop signs, when parking and parked, and other idle-operation situation, the miss begins to return.

In the meantime I'm wondering, if this is connected to the ECU, should not that have shown up on the dealer's (presumably) sophisticated analysis equipment? Likewise the coil packs? They fussed around testing the engine for the better part of two hours, and concluded that the misfire was moving around to what I interpreted as applying to all eight cylinders.

Based on the recommendations made here, I'm having the timing belt (etc.) replaced on Monday. If the misfire has not improved by then (in response to fuel additive), we'll dig deeper. MarkT

 

If that is the original timing belt, don't drive it. Have the belt changed first! every 90k or 9 years is the maintenance interval. Failure is catastrophic.

 

NickB wrote: It's worth whatever the MSRP shows on your sticker and then some if you sell it the right way. $30k plus is what they've been going for on Bring a Trailer if I remember right.

What's the story on this truck? Post up some pics we'd love to see it.
---------------

Apologies for the delay in responding, but for some reason new list replies have stopped appearing via e-mail notice. In any case, I am still working to repair damage from a severe lightning strike, and accompanying prolonged Internet outage, so it will be a while before I have time to take and post some photos.'

That said, the truck is what I would call a charcoal gray, with matching cloth interior. It completely stock, other than having a Toyota brand bed lining.

The story is too convoluted to tell here, but suffice it to say that I bought the truck new from the dealership, in January of 2004, for reasons connected to a divorce. As stated earlier in response to Shifty, I've tried to drive it fairly regularly on trips of 25 to 75 miles each, and have avoided most local, stop-and-go driving with it.

Thank you for the info. on resale value. Because of its perfect size, I'd really like to keep it for another twenty years or so. MarkT

 

Try turning on the A/C full blast while it's misfiring at idle. If the misfires go away, that could very well indicate a timing issue. Weak grounds/power cabling could do it too.

You'd think they'd be able to tell, right? I don't know enough about what they used, though. We do have at least one 1st Gen owner + Toyota mech on the forum, but I feel bad every time I tag the guy, so I'm not going to do it, knowing you need to get the timing belt swapped anyway, and it may fix this.

 

Thanks, Shifty. At idle, it does misfire during max. AC operation. Something tangential I've been curious about: even with the AC explicitly turned off via the push-button on the dash panel, I still hear a periodic under-the-hood "gasp," apparently coming from the AC's compressor. I haven't heard this on any other vehicle I've owned.

Meanwhile, FWIIW, I am once again receiving e-mail notifications of replies to my forum posts, without having made any changes in Settings. Will miracles never cease? MarkT

 

ac compressor will still engage if vent is set to defrost, even with ac button turned off.

glad your email notifications are working again.

you going to upload some pictures of this low mileage truck????? Please

 

Previous reply truncated: Still working to recover from lightning damage (not to mention recent damage from 85-MPH straight-line winds). Stay tuned.... MarkT