"Tokay" > writes:

>I change the spark plugs every 3 oil changes (I'm experimenting to find
>which gives best economy) but I tried switching out the spark plugs
>from Platinum +4's back to standard plugs when I first noticed the
>sound,

+4's sucked in my car. Standard NGKs were much better and cheaper.

>but that dropped performance significantly, and made my engine
>noisier (I have no idea why, doesn't make sense to me that it should
>get louder with standard plugs).

Tighten them down good? Right heat range and right gap? I agree that standard
plugs should be fine if they are indeed the correct plugs.

>I changed the plug wires at the turn of 100k, but I thought they were
>good for 50k or more....

They can be. Some are much worse. The rubber insulation dries out with age,
cracks, and the wire discharges somewhere where it shouldn't.

>I change my oil religiously at 3k (It's just my thing, probably don't
>need to be so anal about it), and I use full synthetic, and a midgrade
>oil filter (Fram tough duty), the air filter I change less religiously
>(every 3 oil changes or whenever I think it's getting bad)

Sounds like my own maintenance plan. Except I use Pennzoil for no particular
reason.

>for my injectors, even boosted my mileage, but the noise persists.

I can't remember, if you mentioned is the noise accompanied by a noticeable
power loss? If so, it could be ping given that your injectors, plugs and wires
seem to be in good condition. Try premium gas. If that doesn't change it,
check your timing. Timing that has been either retarded or advanced from spec
could cause ping.

Something else that is worth mentioning is that if your EGR is not working
correctly, the motor will want to ping when it is hot. If it pings when cold
then the problem is likely to be somewhere else. You can do a quick visual
examination of the valve by having someone rev the motor and seeing if the
diaphragm moves freely. However, the valve could be working and yet the
exhaust passages or intake manifold passage is clogged with carbon.