2004 V6 4Runner - 200k mile tuneup

Hey folks,

My dad has a 2004 4Runner V6 sport that has over 200k miles on it now. With it being a great Toyota vehicle, it has made it this far with fairly minimal maintenance. He goes cheap on the oil changes and uses Quaker State 5W30 and whatever filter is the cheapest. We've replaced the rotors and pads once and he's had it tuned up before at around 130k miles.

It still drives great, but his complaints are that the gas mileage just sucks and that his heater will sometimes blow cold.

• For the heat issue, I think a simple drain/fill or flush of the coolant would do the trick. There could also be a bubble in the heater core that shifts around as he drives and causes the intermittent heat.

• For the MPG, I am thinking of giving it a tune up with the following parts:
  • New upstream O2 sensors
  • New downstream O2 sensors
  • New Coils/Plugs
  • New air filter
  • Clean MAF sensor

And then I'll also hit the following parts just for safety sake:

• New serpentine belt
• New fuel filter - Not sure if these can be changed on the 4R? I know my Taco doesn't have one.
• New radiator cap - I know it has never been replaced.. are these worth changing out if they are still working OK?

Did I miss any items in my tune up? We probably won't tackle suspension items (tie rods, ball joints, etc) or driveline (trans/diff) at this time.

 

I'd avoid replacing multiple expensive parts that are most likely still functioning properly for the sake of ~1-2mpg that may or may not be "lost". How long has the mpg sucked for? Most of its life I'd assume lol.

Change the plugs and air filter at the recommended intervals.

 

I like your proposed solutions for the tuneup. For me, I'm super particular about my fluids so when I see anything other than AMSOIL I cringe. I use AMSOIL in the front & rear differentials, transfer case, and engine. Toyota fluid for the trans. For the MPG tuneup, I think coils/plugs, air filter and MAF sensor cleaning are good. As for the O2 sensors, I don't think it's worth the money to replace unless you're having codes pop up for them. Fuel filter is never a bad idea permitting that the 4th gen has one to replace. Serpentine belt, sure. Radiator cap, yes. The gasket can wear out over time so it's not a bad idea to replace that. So overall I believe you have the right idea for a tuneup. I've noticed a 2 MPG decrease lately in my 3rd gen, so I decided to buy some

$25 BG 44K Fuel System Cleaner Power Enhancer 11oz.

BG 44K from the dealer and put it in the gas tank. I haven't gone through the entire tank yet but I hope it does at least something for the mileage.

 

I just saw your post about your 4Runner. I am helping a friend buy a used car. I ran into a 2006 GMC Envoy with 150,000 miles and a 2006 4Runner V-6 with 303,000 miles. ABSOLUTELY no comparison! Honestly, it was quite freaky how good that 4Runner rode and drove compared to the GMC. The A/C was so cold too. I've thought about looking at these now. Proper maintenance and TLC will make these run forever. Makes me wonder how many miles my Tacoma will get.