I have 110k miles on my 2009 GX and plan on getting oil change done (synthetic) and spark plugs replaced by an independent mechanic who is also a friend of mine.

I've already bought the Denso spark plugs. Since I'm not very mechanically inclined, I'd like your feedback as to what other things I should get replaced/cleaned as part of tune-up to improve performance and hopefully get better gas mileage. I used to average 17-18 mpg until about a year ago (100k miles), but since then it has dropped to around 12 mpg. Here is what I'm considering:
1. Replace spark plugs
2. Clean throttle body
3. Clean MAF?
4. Replace PCV valve?
5. Run a bottle of Seafoam??
Anything else?

I have already replaced the air filter. Should I get fuel injectors cleaned? - would that be expensive? I run Chevron fuel injector cleaner every 10k miles. The car has regularly been serviced every 5k miles and is overall in very good condition so I'd like to maintain moving forward as I plan to keep it for a while.

Another question I have is that I got the differential fluid replaced 10k miles ago by a Toyota dealer who charged around $230. Do you think they also replaced the transfer case fluid? I asked the service adviser at my next service and he said yes it is included but I'm not too sure about it. Is there any way for my mechanic can verify that without dumping all the fluid?

I'm sure my mechanic would know all this stuff, but I always like to go prepared so I don't appear very ignorant about all these things. Any guidance you can provide would be helpful.

Thanks.

 

Has timing belt service, water pump, drive belt, etc been done before? As far as transfer case goes, you could go under the truck and remove the fill hole bolt and stick your finger in there and wipe it on a white napkin to see if it is cherry red or do-do brown. That is what I would do. 10k and the diffy fluids should be a nice bright red. Would not clean the injectors if you are running a cleaner through. Have you flushed your power steering fluid or brake fluid yet? If you have not done the TB, water pump etc, then atleast change your coolant with 50/50 pink

 

Yes, the timing belt & water pump were changed at 90k mile service by Lexus dealer. The power steering fluid is clear since I checked it recently.
Good to know TC fluid can be easily be checked without letting it drain.

So you think my tune-up list is fine? Anything you would add/remove?

 

Engine air filter
Cabin air filter

How long since you changed the brake fluid? Should be done every 3 years, or every 2 years if you live near the coast or other high-humidity area.

Chip H.

 

Transfer case uses 75w90 gear oil, same as the F&R diffs, not ATF. Not all gear oil is red, but you can still get an idea of the condition of the fluid with the finger dip test.

 

Yes sir you are correct on color, but the Toyota fluids are red as is the mobile 1 synthetic 75-90

 

Brake fluid was changed just a few months ago when I replaced the brake pads.
I also got both engine and cabin air filters replaced as well.

 

So, there is nothing else to add to my tune-up list? Are all 5 items valid? I'm not even sure about # 3-5 if that is necessary since I'm doing #1 & 2.

 

How about the drive belt? Should that be replaced at this point if it hasn't been done already?
I'll try to search for the part number so I can pick it up from the Toyota dealer, but if anyone has that handy please let me know.
Are there any other belts in our engine that should be checked/replaced?

 

what was past oil change interval history? If it was prolonged intervals you may want to consider replacing the PCV

 

It has been every 5k miles from day one until now. But I don't think this will be an expensive part, so I'm considering replacing it anyway - might help with better mpg or an even smoother ride?

 

Drive belt only external belt, 5 min job, just and elbow scraper. Second set of hands to help flip it around pulleys while you hold tensioner helps