99 Avalon spark plugs

[inspmm]

I'm coming up on 60k miles and the Toyota maintenance schedule calls for spark plug replacement . I've heard that the original stock plugs are good for many miles past 60k. What's your experience?

[fj40supraman]

They are dual eletrode platinum Densos. Price the OEMs and you will see that they are quite expensive. I'd not worry about them until 100k unless you are having problems (rough idle, bad fuel economomy, etc...)

[toyomoho]

Spark plug replacement is most likely based on maintaining emissions standards rather actual plug life, platinum plugs should last at least 100K.

[inspmm]

Thank's for the info..... car runs fine no problems. Think I'll leave the plugs alone.

[2000-Avalon]

I bought my 97 avalon with 95k miles..... replaced the original plugs @ 96k miles and they were still perfect. I just got some toyota ones for $6 a piece with my discount so it was'nt harsh at all on the wallet. Good luck.

[Hajoca]

The plugs are about US$10 each, or here 12.50 CDN. for the rear bank, well worth the money because they are quite difficult to change out.

[97avy]

Originally Posted by Hajoca

The plugs are about US$10 each, or here 12.50 CDN. for the rear bank, well worth the money because they are quite difficult to change out.

I'm planning on replacing the plugs on my 97 Avalon with 160k, I bought the car with 140k and owner did'nt have receipts. The idle is a slight bit rough, but still heavily impressed with the car.

anyone have a part number for the plugs? Are they Denso? Can they be bought outside (autozone, kragen, etc.)


anyone have instructions on how to change them out? Do I have to remove the rear upper intake manifold?

Thanks in advance everyone,

[cexsiman]

part numbers should be in the manual if you have it, and i can tell you that the front bank is an easy change out, but the rear bank is a tight fit. you might even want to try getting the car up in the air and working on it from underneath if you can. you dont NEEED to take it off, but get someone with small arms and thick sleeves to help you out.

[TMack409]

Originally Posted by 97avy

I'm planning on replacing the plugs on my 97 Avalon with 160k, I bought the car with 140k and owner did'nt have receipts. The idle is a slight bit rough, but still heavily impressed with the car.

anyone have a part number for the plugs? Are they Denso? Can they be bought outside (autozone, kragen, etc.)


anyone have instructions on how to change them out? Do I have to remove the rear upper intake manifold?

Thanks in advance everyone,

The plugs are cheaper at the dealer than most anywhere else.....about $10 each. FWIW, the parts counter guy at my local dealership said many lift the intake manifold off to get at the rear plugs. Rubbish! They are indeed a struggle, but I've found that if the engine is warm, the plug boots will come off a lot easier. Must have powerful grip! (Perhaps they are harder to reach on other models - but mine's a 1996 and I've never had a problem.) I replace my plugs every 60K per the manual - but I do think that's conservative. I may push mine a bit longer on the next go round.......LOL at 180K miles, I don't know how many more times I'll be dealing with it anyways ;-)

Btw, your rough idle is most likely due to dirty butterfly valve in throttle body.

[golfgod]

Changed my plugs at 120K while replacing valve cover gaskets after I bought the car. It had Denso in it, was running fine and looked like original, but previous owner didnt log maintenance so I cant be sure.

Just for kicks I went out to see if I could get at the rear. The trick was using my cheap 3/8" wobble extensions with spark plug socket. The stack up was...spark plug socket, then 3" extension, 2", 1" and then a stub swivel handle craftsman ratchet. Tip...had to drop some of the pieces in one at a time because the entire stack up wont slide in tube all together.

I agree with TMack409. Try to clean up intake to help rough idle. New air filter and the Seafoam treatment in PCV valve hose would do wonders.

[avalonian]

hrm Question I have 125k on mine. my start up is a bit rough. takes 2 seconds to turn over. In need of new spark plugs? My idle is fine and steady.

[TMack409]

Originally Posted by avalonian

hrm Question I have 125k on mine. my start up is a bit rough. takes 2 seconds to turn over. In need of new spark plugs? My idle is fine and steady.

I'm probably the wrong person to ask, since I change mine (1996 Avalon) by the book at 60K. But I would say you are more than due...... Rough starts are cured by premium fuel. But I can't afford the luxury of premium petrol during these times.

[Hajoca]

Have you cleaned out IAC, throttle body, and replaced fuel and air filters?

Originally Posted by avalonian

hrm Question I have 125k on mine. my start up is a bit rough. takes 2 seconds to turn over. In need of new spark plugs? My idle is fine and steady.

[fj40supraman]

True Story
When I bought my first Avy It had 150K miles, had it in to the dealer to get something and I asked the service manager when should I have the wires and plugs changed. He asked how does it run. I said no problems and he replied that they don't change them based on interval anymore as they are platinum plugs. So I let them go and it's still running on them same plugs (someone else has it now) with over 230K. Still runs fine.
I recently put NGK Iridiums in my Avy and they seem to be the same as before. They have a slightly smaller electrode (more spark), but I can't tell the difference. They are suppose to last a long time. I also did the wires while I was messing with it. Back ones are a pain, but a swivel ratchet as listed above helps. Used one long extension and put antiseize on them, considering they last 100K. Hopefully I can put in another set at 300K!

[TMack409]

When the gaps in the plugs get really wide from wear - this puts a strain on the rest of the ignition system - mainly the coils, which can break down from the stress. Also, as the ignition leads wear out, they require more energy from the coil to fire the plug - so don't neglect the wires either. Plugs are cheaper to replace, than coils. Also, since our engines have only three coils, these coils work harder than a 'coil over' at each plug. That said, each coil is firing two spark plugs at the same time (one of which is of course, a waste spark but nonetheless coil energy is required). So, as I said, super wide gaps make for excessive loads on the coils.

Whilst 60K may indeed be conservative replacement interval for the OEM plug, I can't recommend placing them on the ignore list forever.............