Hello, I have a couple old Toyotas. One’s a 1999 4Runner Limited with about 170k miles and the other is a 2007 sienna with about 340k miles.
I’ve had the sienna since it was new, so I know this van very well. It still drives like it’s new, the engine runs very smooth, transmission shifts smooth, everything still sounds and feels great (besides some suspension attention necessary). My problem is figuring out if I should get new fuel injectors, pumps, and maybe a filter. I’ve used the fuel injector cleaning stuff, it doesn’t seem to help. But I know I used to get 430 miles In a tank, and now I roughly get 320. The 4Runner is getting 230-250. This kills me, knowing people get 400 miles with 2/3 the fuel tank size. Keep in mind I moved to Texas, so the majority of my driving is highway. You would think highway driving would help though? I know speed does affect this too at a point, but how much? Or maybe A/C just does THAT much. Please advise.
Clarification: Can you post the short term and long term fuel trims for each vehicle? Also, post the fuel pressure test results.
I know speed does affect this too at a point, but how much?
Your fuel burn quadruples every time you double your RPMs. Let's say your idle speed is 1,000 RPMs, and you're driving down the road at 2,000 RPMs. The engine is burning 4x the amount of gas to go that fast. If you floor it and hit 5,000 RPMs, the engine is burning 25x the amount of fuel that it did at idle! They put transmissions in cars to keep them in an efficient range. 2,000 RPMs can get you going 20 MPH or 55 MPH if you have the right gear ratio.
That's under ideal physics. I checked my truck with my scan tool the other day to see how accurate the idealized science is, it's quite close.
Get a scan tool with Live Data and check out the fuel trims. That will give you a good idea on how well the engines are running. +/- are lean and rich.
I’ve used the fuel injector cleaning stuff, it doesn’t seem to help.
If it's really dirty, it may take a few bottles. My '99 Ranger was running rich by 9 to 11% a few months ago. I ran several bottles of Gumout, Scotty's old go-to through it, and it's now almost perfect. Your check engine light won't come on until it's closer to +/-20%.
This is helpful. I’ll get 100 bottles of the fuel injector cleaners (jk) and I’ll look into getting a scan tool to see accurate readings
What speed do you drive at, on the highway? Constant cruising in top gear or?
When was the last time both your vehicles had a tune up? Things like air filter, fuel filter, spark plugs, MAF & throttle body cleaning?
Have you verified your cold tyre pressures are correct?
Do the vehicles have any stored trouble codes? What was the reason for running fuel injector cleaner? Bad fuel trims?
No, there’s no codes at all. I had them dealer maintained actually until just about a year and a half ago when I saw the dealers in Texas are trash. But I still have routine maintenance on time. The 4Runner had spark plugs, water pump, timing belt, and a lot of components changed at around 120k miles just a year and a half ago.
I’m not absolutely stupid with the throttle, but I do have a lead foot. I do like to step on it from time to time, I like to go over 80 mph at times. I used to even hit speeds of 100. However, I know my Toyotas and they forgive like that. Since the fuel prices went up I drive on cruise and don’t go over 75 and am getting the same results. But maybe that rough driving time to time has wore it out?
Also there is no reason to guess I need anything. Everything seems fine. That’s why I ask, maybe it’s worth replacing some of those parts but if it ain’t broke why fix it
Watch this video -
https://youtu.be/aRQ_Cr5vu7A
That’s the thing. I know my tire pressure, I’ve been slow off the light and barely use my brakes as I try to coast as much as possible. I even turn the cruise off when I approach a hill so that it doesn’t automatically accelerate real hard (especially in older cruise control systems). I do turn the air off on my morning drives. I even use the GasBuddy app. Like all of those things he listed I keep in mind. All maintenance is done, hence why they have run so many miles and still behave like new. Every time I fill up I reset my trip computer too. So with all those things In check, I did notice 40 miles or so in difference. Now on my Mercedes’ or other vehicles the difference can be much greater, but I know my Toyotas well, and I’m just not getting the same miles as I used to. So I assume that the fuel pump and injectors aren’t really necessary to swap? Maybe Toyotas really do wear out over time.
Assuming everything on the vehicle is stock, check your brakes to inspect for any sticking/dragging, while driving.
With that mileage, your engines are wearing out. Get a compression check that might explain the poor gas mileage.
Interesante... might just have to get the check. I’m into classic cars, I’ve seen vehicles do lose power over time, but like I said I know this sienna since it was new and it does drive like it still. Idk if you have driven an old 3.5L V6 Sienna but boy they have POWER!! And they’re so smooth. It’s a Texas hot hatch lol. I used to hate it like any young guy hates the minivan but I’ve learned that besides looks and all this this is incredible. Fits more than a Tacoma bed. Fits 8 people. Drives sooooo well and so smooth, better than a lot of new cars tbh. It’s reliable and costs nothing to maintain. I hate the looks in it and I’ve wanted to get rid of it but this thing is too good
Knowing people get 400 miles with 2/3 the fuel tank size
With a 4Runner?
Lol, yeah that’s why I keep the sienna in conversation. The 4Runner is just gonna be this way. I got bigger wheels and lost another few gallons of gas but hey, I’m a proud member of the 4runner cult
With a 4Runner?
Not with my 4Runner.
True. This is the case with any 4Runner.
Sometimes I see another 4Runner and start celebrating and put my rear window up and down and they swerve out the way so fast. Oops. Too many moms in these things. But man this rig has seriously made me think about going electric, which was the opposite reason I got it. To me it’s better than a rolls Royce. Wish you and your pockets all the best at the pump. I found that if you just drive it less it works out alright.