v8 tune up?

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WhiteRubi

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2004 V8 AWD SR5 168,xxx miles.

here are some issues:

gas mileage is around 15 on interstate. not sure if this is normal @ 70-73mph

when I accelerate quickly (mash the gas, and sometimes down shift) i have an odor in the cabin, sulfur/ammonia smell. I'm thinking improperly burned fuel. So, I guess the questions are this

What is normal MPG on a stock suspension/tire v8 AWD?
Do I need a tune up to address MPG as well as the odor?
What are the normal items for a tune up on these trucks?


And lastly, local dealer is replacing the dash. Thanks to the T4R family for informing me that this was an option. They said it would ship in 7 days but that was 3 weeks ago. I wont complain though, its free.
 
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for reference, my 05 V8 w 145k on her gets 18mpg fairly consistently. if the tank is all city, its 17mpg. if its all highway under 75mph, I have pushed 19.9 (so close to 20). this is with premium 89 (or 91 if available). for every level of gas I drop it takes 1 mpg on average.

I purchased in May '15, immediately did plugs, synth oil, HCF delete and a major seafoam treatment.

make sure your tires' pressures are to spec. change the air filter if needed. put good gas in it. look into new plugs/oil and possibly a seafoam treatment. been using the stuff for years and on vehicles with over 100k miles it can, and usually does, make a significant difference.

we all have the sulfur smell. some says its the cats, others have other opinions. consensus seems to be: don't drive with the rear window open & do the tailpipe out the side mod. its better than replacing the cats, which doesn't help all that much on pre-06's IIRC
 
If it's on the original spark plugs, they should be replaced. They are good for about 100,000 miles.

You should probably might consider having the valve clearance checked/adjusted. It's kind of expensive because it's a bit involved, but it might be time if it hasn't ever been done.

The timing belt should have been replaced around 90,000 miles, and there should be a sticker somewhere indicating when it was replaced. If you suspect it hasn't been done, do that right away. There won't be any symptoms of a worn timing belt until it breaks and possibly causes engine damage.

The mileage sounds a bit low, but I don't know what's normal for the older V8s (they updated them around 2005 or 2006 with more VVT-i, I think, so you can't directly compare old/new)
 
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m85476585 said:
If it's on the original spark plugs, they should be replaced. They are good for about 100,000 miles.

You should probably have the valve clearance checked/adjusted. It's kind of expensive because it's a bit involved, but it might be time if it hasn't ever been done.

The timing belt should have been replaced around 90,000 miles, and there should be a sticker somewhere indicating when it was replaced. If you suspect it hasn't been done, do that right away. There won't be any symptoms of a worn timing belt until it breaks and possibly causes engine damage.

The mileage sounds a bit low, but I don't know what's normal for the older V8s (they updated them around 2005 or 2006 with more VVT-i, I think, so you can't directly compare old/new)
Click to expand...

This is really bad advice. The V8 is bombproof. Valve clearances will be fine unless it was abused and not maintained.

Replace plugs, clean TB, inspect or replace air filter, change oil, replace PCV valve and reevaluate. Check for frozen calipers, poor tire tread/pressure etc.
 
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What I should have said is that it might be a good idea to have the valve clearance checked if everything else is OK and you still suspect something is not right with the engine. I didn't mean to imply that it's likely the problem, but that's how my previous post sounds.

http://www.toyota-4runner.org/4th-g...rance-inspection-2003-4-7l-v8-worthwhile.html

It is something that can change with time, and if you want your engine to be running as well as it can be, then it's something to consider checking.
 
Id skip the valve check.. Many here have well over 250k miles without it.

Shit a used ebay motor can be had for 1100. 600-800 for labor or DIY

When it fails.. swap in.. Or spend 1k on 2 valve checks.. that (checking not re shim)
 
MPG is so subjective to how a person drives !

Dont let the timing belt guys scare your, do a quick search and you will see both sides of the story. Most horrors of timing belt failure are exaggerated from those 80s and 90s Hondas...the only one I have ever seen fail was due to an oil leak.

That smell, enjoy it, learn to love it...smells like a Toyota!

Spend your money on a cold air intake, and a good cat back exhaust...its more fun!


I would service the transmission, thats the one most folks neglect and Id suspect the failure of just about every old car on the road. Its easy to do, if you have the oil cooler lines, drop that pan too, get that filter

and lube that driveline for silky smooth stops
 
I have a cat-back system, CAI and super chip in my rig, larger tires and still get 15 city and 19 highway. Done the plugs religiously at 100K and seafoam as well. Run Amsoil in everything except the tranny and radiator, use only Toyota OEM for these. 207K miles and runs like a champ! If you need to invest IMHO....cat back system and CAI are good ways to improve in and best of all it sounds awesome when you mash it. Don't expect great mileage doing that all day!
 
rooost said:
MPG is so subjective to how a person drives !

Dont let the timing belt guys scare your, do a quick search and you will see both sides of the story. Most horrors of timing belt failure are exaggerated from those 80s and 90s Hondas...the only one I have ever seen fail was due to an oil leak.

That smell, enjoy it, learn to love it...smells like a Toyota!

Spend your money on a cold air intake, and a good cat back exhaust...its more fun!


I would service the transmission, thats the one most folks neglect and Id suspect the failure of just about every old car on the road. Its easy to do, if you have the oil cooler lines, drop that pan too, get that filter

and lube that driveline for silky smooth stops
Click to expand...


Very subjective :) Based on how modified your vehicle is makes a huge difference (roof rack? Tire pressure?, etc.). I have a 3.5" lift, CBI bumper, and nearly 34" tires. I used to get great mileage on my '05 V8, but now...everything matters, including tire pressure.

Related to all of the above advice, I have always cleaned my MAF along with TB, and the truck runs noticeably smoother with regular synthetic oil changes and air filter recharging (k&n factory replacement).

Good luck!
 
Thanks for the info fellas.

Then timing belt was done as was all recommended maintenance by previous owner. I just wanted to get this stuff lined out before I lift it. I don't drive much as I work from home but if I can gain a few mpg by a tune up, then I'll do it, especially knowing that with 285s after the lift it will likely drop signicantly.
 
Since the OP is talking about maintenance, I'm wondering is there a service interval for the spark plug wires ? I'm about the same millage as the OP.

Other useful info here, thanks OP for posting.

Thanks.
 
i have an 03 v8 with 139k miles. I commute with it 320 miles a week. I get 15.98 MPG for mixed highway/city.

I have changed spark plugs, oil, filters and diff fluid. Havent looked at the PCV valve to change. Havent needed to.

I think your MPG is right on par. Im on 285s, lifted with bat wings on the front end. Also have my speedo adjusted and its GPS confirmed correct.
 
Are the V8 4runners actually able to take premium?
What are the advantages or disadvantages (if any) to running premium?
 
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