Why is my 1999 V6 so weak?

Yeah the manuals up 70 out of Denver do pretty well. My 3.4 in my old runner with 34's was good unless traffic stopped prior to the tunnel. Then it was 50-55mph max for me. But it was an auto.

 

It's no fun if traffic stops me anywhere along a pass. But even at a cruise, my truck struggles to push it much over 60. And I'm in third, but that's the top gear of the auto's, not counting overdrive.

 

I just started a new thread about a different problem that might be related to my truck's performance issues:

http://www.tacomaworld.com/forum/1st-gen-tacomas/278298-brake-booster-engine-power.html

 

I got the HP back. My truck now feels similar to the Prerunner I had.

I've spent the past 5 months thinking I was chasing an A/F issue. Cleaned my MAF sensor a billion times, new plugs, fuel filter, cleaned the throttle body, IAC valve, premium gas, tire pressure, etc. Even got an Ultra Gauge to monitor a bunch of numbers that I don't totally understand.

In the end, what did I do that finally made a significant difference?

CHANGED ALL FLUIDS TO SYNTHETIC, including ATF.

The change was instantaneous. The weird thing is, when I first got the truck, I DID change all the fluids, but I used Dino. Most of it I bought at the stealership. And the thing felt like it had glue in the gears, which I mistook for engine weakness.

Now, it feels properly lubed and has pep back. It doesn't bog down on hills. I wouldn't have thought the difference would be so noticeable, but it is. And now I can stop monitoring my timing advance, looking for clues. And I can keep my 265/75/r16 tires.

 

So you did diff, tranny and motor? Good to hear! I need to go through and do my diffs and tranny.

 

Front and rear diffs, transfer case, transmission, and engine oil. All synthetic. Do it.

 

Nice. Just did my tranny last night with MT-90 syn. Doing the diffs tonight. Will eventually get to the transfer case. Engine is already synth.

 

Out of curiosity, when you did the compression test, what numbers did you find?

 

Ever since I bought my Taco, in Nov 2011, with 75K miles, it felt kinda sluggish. Every three months I would throw a large bottle of Techron, and it would drive better for a tank or two and then felt sluggish again.


Two months ago, I threw two bottles of techron in a 4 week span. BOOM, no more slugishness. Of course, I replaced the oil after the second bottle. But overall, the engine feels A LOT better. I no longer have to turn the OD off when driving over steep hills, which are all over, here in Denver.

Mileage is mostly unchanged, but drivability is much improved.

 

But do you turn the OD off when going down hills? To remove that gear and let 3rd do some braking?

P.S. I lived part of my childhood in Brandon, FL. Spent good time playing in the creeks there.

 

I'm not sure if that is directed to me. I didn't ever do a compression test. I'd still like to just to see where the numbers are, but I bet they are in spec (whatever that is).