High mileage oil questions

[Kindergardener]

I use 91 octane gas (Costco), and never have pinging.
I have used full syn a few times, and no leak or consumption increase.my car just reached 100k miles.I will keep using Syn if I want to, no worry.
15MPG on highway is a bit too low even with the driving condition you described,( I could be wrong), have you checked the PCV or changed fuel filter?

 

[disel1978]

MGregoir...thanks so much solid info and I will do all. Yea when i bought the car 2 years ago I got the K&N and never really notice a diffrence, but really had nothing to compare it with since I had just bought the car. I will try the Amsoil though. So Seafaom in the combustion chambers...hard to do? I know my way around a car but I am not hardcore...I have run Seafoam through my gas as staed earlier...ever 6k or so I guess. I really only notice it when going up hill and more in the summer so...not a big deal but whatever I can do to make it run better I guess...thanks.


Kindergardener....not sure on octane but I get gas at Cheveron almost always...super here and there ( not lately with gas $$) I guess if I have been usingsyn blen Castrol I am sure full syn Pennzoil will be better, as it sounds like it is. I agree the driving condition can't cause up to a 5-8mph diffrence then the rest of you guys...even if I drive 80...it is set on cruise..not hot roding... PCV I have not checked what do I look for and what not? And last time I had a tune up about 1yr was when the fuel filter was changed...any other sugesstions?

 

[Kindergardener]

Diesel, I am not sure if PCV would affect MPG, if you want, PM me, I will send you the info.
I think my MPG is quite good for 99QX, but I have done all the maintenance I don't know which part gets the credit, may be a combination of all:timing belt, water pump, pcv, trans flush,PSF, brake fluid,new belts,coolant,new spark plugs, differential (front and rear)and transfer case all fluids changed plus an easy driving.

 

[disel1978]

Since I bought my Qx4 this is what I have had done:

Timing belt
New Water pump
All new belts
All new Hoses
New Radiator
New Plugs/wires
New battery
Throttle body/MAF cleaned
Front and Rear diff fluids done
Trans/ and Transfer case 4x4 fluids done
All (4) new KYB shocks and struts
All new Ceramic Brakes (2 times since I owned it) New rotors last brake job. Bearing repacked/all fluids replaced and flushed
Maint. change oil ever 3k was using Castrol Syntec blend 5w-30
K&N air filter and Wix oil filter since I have owned it
Run Sea foam in gas every other oil change
Clean engine every other oil change

So just about $2,000 in preventative maintenance, my mechanic loves me

So I would think all that I have done and do...should be working for me...just think it's weird I get poor gas mileage compared to others. How do I PM you by the way? And what do you mean by “PSF” in your list of stuff you have done?

Yea would like to know how to clean my MAF, Throttle body, and clean or replace my PCV on my own for my next oil change.

Oh and one last question HA! Since we own pretty much the same car have you ever had an issue with the keyless entry? Mine dose not work and I have changed the battery in the remote? And tried to re program it but not sure if i did it right?

thanks

 

[Cmarti]

Originally Posted By: disel1978
Since I bought my Qx4 this is what I have had done:

Timing belt
New Water pump
All new belts
All new Hoses
New Radiator
New Plugs/wires
New battery
Throttle body/MAF cleaned
Front and Rear diff fluids done
Trans/ and Transfer case 4x4 fluids done
All (4) new KYB shocks and struts
All new Ceramic Brakes (2 times since I owned it) New rotors last brake job. Bearing repacked/all fluids replaced and flushed
Maint. change oil ever 3k was using Castrol Syntec blend 5w-30
K&N air filter and Wix oil filter since I have owned it
Run Sea foam in gas every other oil change
Clean engine every other oil change

So just about $2,000 in preventative maintenance, my mechanic loves me.



Sometimes we love too much......

 

[Kindergardener]

Check PM

 

[88luder]

Use the auto RX. I am in the middle of my clean phase and car is already running better. No need for expensive oils when using auto RX. Best is to just use some cheap 5w30 supertech from walmart with one of their filters as well. Definitely change out your PCV valve as well, bad PCV would cause sludge thus decreasing your MPG.

BTW: I personally wouldn't use any solvents in your engine, it will eat through your engine's seals. Which is why auto Rx would be better IMHO. Also, you should try using chevron fuel system cleaner. I never have liked seafoam products.