Nasty spark plugs. Should I worry?

First post but I’ve been lurking for awhile. Bought a 2011 4.0 right at 170k. There are oil change records in carfax but nothing else so I did all fluids filters etc. Pulled the spark plugs today a viola. The original plugs. Half NGK half denso and they are nasty. Question is there something else I should do as an extra precaution due to neglect or just roll with it?

 

Id just feel better knowing the plugs have been changed and not worry. I bet it runs better now.

 

What plugs did you replace with?

 

Denso. And it feels like a different engine.

 

You did all fluids? Brake, coolent, power steering? F&R diff and transfer case wont hurt. You will get a lot differing opinions about transmission fluid but I would.

Serpentine belt?

 

Drain and fill transmission but yeah everything else. Belt looks brand new.

 

I wouldn't worry, plugs are supposed to be changed every 30k, if you just got the truck who knows how long they've been in there.

Edit: since half NGK and half Denso they are likely original, and are about 140k overdue

 

Suggest to change tranny fluid and the filter.

Easy task, just a little messy. RockAuto has filter with gasket for about $20 + shipping..... you'll need 4-6 quarts of Tranny fluid. Check the manual for type. IIRC, Valvoline MaxLife ATF is compatible with Toyota WS.

 

Sorry, forgot to 2nd the Serp belt. That mileage, I'd definitely change the belt, tensioner and idler pulleys.

RockAuto has a Serp kit with all the goodies for about $190.

Local Toyota dealer quoted nearly $1200 for this work.

Tranny fluid w/filter, no flush, dealer quote was $650.

 

Give your throttle body, mass air flow sensor and fuel injectors a good cleaning

 

I would say that those are the factory plugs. I bought my truck with 115,000 miles on it and it had factory plugs. Surprisingly, the truck great and yours probably was too.

 

gap so big you could drive a firetruck through there.

Your coil packs and truck are going to love you with some fresh plugs.

 

Those have never been changed. Good think ya changed em!

 

I wonder what the gap is on those. The dealer I use charged 200 for the tyranny drain and fill, but flush is bad!

 

Might want to add coolant to the list.

 

Those plugs look fantastic for the mileage, great job replacing

Baseline your fluids and drive

Well done

 

DOesnt look like you have anything to worry about. As mentioned, huge gap lol, but thats expected. Otherwise, I wouldn't even call them nasty looking. I've seen much worse.

 

If you still have original plugs, I would assume NOTHING has been done. Go through everything, and start your own schedule. Don't forget little things like your PCV valve. It was also mentioned, but I'll second doing a throttle body and MAF clean. Use a good injector cleaner in your gas for a couple of tanks.

 

I wouldn't be too worried about the engine itself. I'm not sure about what your truck recommends, but the longest I see recommended for spark plugs is 100k. 170k is definitely too far. As badger stated above, assume nothing else has been done because you just don't know.

 

Gen 2 V-6, spark plug change interval is 30,000 miles.

Suggest to the OP to go ahead and perform all the maintenance on all items from 5-100 kmiles. This will essentially 0 (zero) the maintenance schedule.

There is a detailed Sticky in the 2nd Gen Forum with everything you'll need.

The units in this list is kmiles:
Eng Oil/Filter 5
Prop Shaft 10
Cabin Filter 15
Fr. Diff 30
Rr. Diff 30
Xfer Case 30
MAF 30
Throttle Body 30
Spark Plug 30
PCV 50
Pwr Steer 50
Brakes 60
Coolant 100
Auto Trans 100
Serp Belt 100
Idler Pulleys 100

There are roughly 4 major maintenance intervlas. <15, 30, 50-60, 100 kmiles.