Should I change spark plugs and shocks/struts when all's well?

[SiennaDriver]

140K on a 2000 Sienna with original Denso PK20TR11 plugs, starts and runs fine except for grossly lacking pep getting up to speed, gas mileage similar to when new (17-21 MPG summers, less winters).

I took a plug out and it looked fine, light tan with a what looked like a proper gap.

Should I replace them or leave well enough alone? Will it make any difference?

Same question for the shocks/struts. Never been replaced. Seems to bounce along just fine. Will replacing them make a difference?

[Black Sunshine]

Originally Posted by SiennaDriver

140K on a 2000 Sienna with original Denso PK20TR11 plugs, starts and runs fine except for grossly lacking pep getting up to speed, gas mileage similar to when new (17-21 MPG summers, less winters).

I took a plug out and it looked fine, light tan with a what looked like a proper gap.

Should I replace them or leave well enough alone? Will it make any difference?

Same question for the shocks/struts. Never been replaced. Seems to bounce along just fine. Will replacing them make a difference?

Grossly lacking pep getting up to speed compared to what? Compared to when it was new or compared to your Corvette? Your fuel economy is the same as mine but at 225,000 miles mine still has no problem getting up to 80mph by the end of the entrance ramp. I've changed my plugs twice now. I think that the recommended interval is 100,000 miles. Make sure to use iridium plugs.

[wiswind]

I will echo Black Sunshine's advice but add that I would make sure to get the EXACT same number spark plug.
My 2003 lists both a DENSO and a NGK number.......either one would be fine, but use the number that they list.

My 2003 lists a different number than the 2000 model year.
The DENSO PK20TR11 is a Double Platinum plug, platinum enhancement on BOTH the center electrode and ground tab.
They are rated by DENSO for "In Excess of 60K miles"
The IK20 "Iridium Power" plugs that claim better performance are rated by DENSO for only 30K miles.....so stay away from those.

Shocks and struts usually don't die, they fade away.
However, struts usually last a long time......shocks are much easier to replace than struts.

[SiennaDriver]

Found a great single shop mechanic who could have taken me for a lot more. For $180 he diagnosed and changed a loose (rattling) upper strut mount on the passenger side and assured me the fronts were good to go and to replace the back shocks sometime down the road. Toyota was happy to replace everything on both sides to fix that rattle for over 2k.

He also pointed out a leaking rear valve cover gasket I wasn't aware of, so I guess I'll replace that and it'll be easy to pop the plugs in while the cowl is off.

Was also told that with a little overdue and planned upcoming maintenance the car will be good for at least 200k, likely 250k. Have never had a car last that long!

Curious to know if changing the plugs will change anything. It's amazing that they've gone so far and look so good.

[TierOneSupplier]

Originally Posted by SiennaDriver

Was also told that with a little overdue and planned upcoming maintenance the car will be good for at least 200k, likely 250k. Have never had a car last that long!

Curious to know if changing the plugs will change anything. It's amazing that they've gone so far and look so good.

These are amazing vehicles. Our '98 is at 289,700 miles and counting. We're driving it to the beach this summer, almost 2,000 miles roundtrip, 100% confident we'll make it there and back just fine. To your question about the plugs, I've changed ours at 60k to 80k intervals and to be honest, I can never really notice any performance improvement with the new plugs. I use the Denso PK20TR11.

(Black Sunshine - I don't recall seeing that you'd installed the iridium plugs, do they make a difference? I talked myself out of installing them last time, but was very close).

I've never done anything to the suspension although that's coming up before our summer road trip. You'll know when it's time to replace yours; when you find yourself steering to avoid manhole covers and other pavement imperfections, it's time. This slowly started happening with our van on a trip we took last year at about 265,000 miles, so at 140,000 you're probably not due yet. However, as wiswind said, suspension woes creep up slowly.

[Black Sunshine]

I've been changing my plugs at around 100,000 mile intervals. The first time was at 120,000 miles. The second at 220,000. The first time I think that I used iridium. Whether they were iridium or not they were plus twos. They had two prongs instead of just one. They still looked functional when I took them out. This time I know that I put iridiums in and I changed the wires and the boot pieces under the coils. I went with the single prong plugs this time. I didn't notice a difference this time and I don't think I did last time. I think that it's more about not having problems than noticing a difference.

The part of my van that has recently been baffling me is the rear brakes. I've never serviced them, never even looked at them. I'm also surprised that the bearings have held up this long with no problems at all. Especially since it's a van. I need to replace the ball joints soon. They have been really loose but with no play for a long time. They're $30 or $40 a piece at the dealer so I just need to break down and get them.

[chuck's sienna]

I've got 252K miles now and just had to have the passenger front wheel bearing replaced. Front struts are still the factory ones, I have never changed them. These vans are the best, they seem to go forever. My goal is to get to 300K.

[chuck's sienna]

Speaking of rear brakes, I just took off both L & R drums and there was still plenty of shoe material left. But does any body know how to fix that banging/clanging sound I hear when stopping? It comes and goes, but is annoying. Sound comes from the rear only.

[Black Sunshine]

I think that I've read about a recall or a TSB that was related to rattling sounds from rear brakes on first generation Siennas. I ignored it because I've never had any problems from mine at all.

[wiswind]

There was a recall for a "squeel" sound from the rear brakes......caused by some sort of harmonic between the drum and other parts.
I ordered the "Improved" drums from TOYOTA (expensive) and it greatly reduced the sound.....only get it once in a while now.
The Original drums were ribbed on the outside, the new ones are Non-ribbed.....meaning that they are smooth on the outside.
I noticed that all the aftermarket drums that I looked at online were of the non-ribbed design.

Before I put the new drums on, I painted the non-friction surfaces on them.