Toyota Repair: 1999 Toyota Sienna Major Tuneup, spark plug wires, plenum chamber

Question
I own a 1999 Toyota Sienna LE. The engine was misfiring and I paid Firestone $100 to analyze. They presented me with an estimate of $900 for a major tuneup: $180 for spark plug wires, $160 for six spark plugs, $75 for the fuel filter, and $48 for a fuel system cleaner, the rest was labor including $41 to remove and replace one spark plug tube and $200 to remove and replace the spark plugs. That comes to $1,000 to diagnose and tune-up. Looks like I will be performing the work myself. Can you please send me the pages from the manual to perform these maintenance items (I've never before replaced a spark plug tube)? I had my tools stolen three times and stopped performing repairs more than 15 years ago. I think that I can afford to buy new tools at these prices. With the money I save, I can also afford postage on my letter regarding this estimate to the Better Business Bureau--I know these prices are WAY out of line.

Answer
I agree, this seems way over even what a dealer would charge, the spark plug wires are nowhere near $180, maybe $80 at the dealer, the spark plugs are platinum tipped and sell for around $14.00 each,we charge about $85 at the dealer to replace the spark plugs because we can do it without removing the intake manifold top plenum chamber, the fuel filter is in the gas tank and not replaceable and I have no idea why they would need to replace a spark plug tube, forget the fuel system cleaner, it's worthless and a waste of money.
If the engine had a misfire the check engine light should have come on and logged a trouble code in the ECU, do you have this information?
There were some problems with igniter coil packs on these engines which may be the only problem, I don't know what the mileage of the van is, you didn't specify but it sounds like it is way too early for any of the parts that firestone recommended need replacement.
The best advice I can give you is to have the toyota dealer diagnose this and make a recommendation, you may be able to solve this for less than $300 if it's only one of the coil packs that has a problem, also have the dealer check for any service bulletins regarding misfire codes, this may save you a lot of money and frustration because just replacing the spark plugs is quite involved, so I recommend that you trust the toyota dealer to resolve this issue.