Why is my 1999 V6 so weak?

This is the fifth Taco I've owned over the years. I love these trucks. My last one was a '04 Prerunner V6, my first V6. I liked the truck and it really had some balls. But alas, i sold it to buy a 4x4.

I picked up a '99 V6 4x4 with under 95k, in great condition and was pleased as punch. But I just took it on a short trip up in the hills for the first time and have discovered that it is noticeably weaker than my '04 Prerunner, particularly on hills and passes. It maxes out at about 10 to 15 mph less.

Is that expected? Was there a significant change in engine build between the '99 and '04 V6?

is the weight difference between these two trucks really enough to account for a drastic difference in power?

Or should I be looking into something in the engine that would account for this loss of power?

I just got the service records from the delearship and they show that at the 60k service the prior owner reported sluggishness on hills and lean run condition. The MAF was changed and that improved it. But I'm not so sure it fixed it entirely.

I'm going to swap out the plugs and wires and see if that helps, but is there something else I should look into, or is it just a normal difference between the trucks? What part of the engine would breakdown and account for the disparity? The truck runs fine otherwise. It's fine on flat ground. I didn't notice all this when I test drove it because I live in a relatively flat area.

In my '04, if I wanted, I could cruise up hills at 80 mph no problem,. In this truck I have it almost floored at around 65mph, with chevy's, fords, and nissans passing me left and right. It feels more like a 4 banger to me or like I'm hauling rocks. And I can't pass people and look like the cool guy in the Toyota!!

Thanks!!

 

any CeL codes auto man ? wouldnt hurt doin a tuneup plugs wires seafoam changin all the fluids including diffs and t case

if u think its that bad maybe a compresssion/leakdowntest?

 

x2.

But I agree with you OP I have a 99 V6 as well and it seems pretty sluggish on hills. Granted I have a 3in lift and skinny 32's but I don't think my tires are much bigger than stock.

 

You've tried basic maintenance? I did a bunch of stuff on my car when I bought it (a 97) just because it's old and I assumed no one did. Fuel filter is a big one, no one ever changes them. Air filter, plugs?

 

http://www.tacomaworld.com/forum/performance-tuning/106205-5vz-fe-potential.html


the 5VZFE engine is famous for:

-being built like an absolute tank
-not a ton of stock HP
-overbuilt enough to be popular to bore and stroke and make 800HP demons [with no danger to the manifold ]


so, it is not a bad motor, just too much metal with gentle stock guts

 

Except he's comparing apples to apples, right? Did the 3.6L change between 99 and 04?

 

Both the trucks are automatic and xtra cabs. same bodies, same weight load. I had the timing belt done asap as well as the other belts and hoses, etc.. Put a new air filter in it. The plug wires and MAF sensor were changed at 60k. I just picked up some new plugs from the stealership, but I haven't put them in yet. We'll see if it improves after that and some fluid changes. If not, I schedule a compression test.

 

Definitely hit the fuel filter while you're at it. Every used car I've bought has had the original one still in there, and unclogging it really helps. Only $20 for a new one.

 

Fuel filter.......roger that!

 

gawd...

....he is comparing 190HP to 190HP expected


yep, the derp is strong in me today

 

Could also be exhaust - o2 sensor, clogged cat, etc. That's all pricier though... But someone who is smarter than me will probably chime in.

 

My truck feels sluggish, but that is only because it has 31's instead of the stock 28's.

Does the truck have larger than stock size tires? Check the sidewall and compare it to the tag in the door jam.

 

could be a clogged up cat

wait...let me rephrase that


could be a clogged up cat

 

yeah, the door calls for 15's and the truck has 16's. Would that make a HUGE difference?

 

to be more clear: the door calls for: P225 75R15
the truck has on it: P265 75R16

 

to be more clear: the door calls for: P225 75R15
the truck has on it: P265 75R16

 

Yeah, it will. you're going from a 28-ish tire to a 32-ish tire. 12% difference. The increased rolling resistance will bog you down for sure. What'd your last truck have?

http://www.tacomaworld.com/forum/tirecalc.php?tires=225-75r15-265-75r16

 

also depends on the type of tire.

I used to run 235/75r15's on AT's
now I run 265/75r16's on load range E MT's


huge difference

 

Yeah, my 96 T100 4x4 with 3.4 took a huge hit going from aluminum wheels with P rated tire to steelies with Es.
what are your mpgs OP?

 

Just more food for thought, the fact that your 04 was a prerunner and this one is 4x4 will probably make a noticeable difference. All that extra weight under the truck means it will be slower and get worse mpg. However all these ^ suggestions will probably help too.