usadaytrader

I have a 2.7L Tacoma. 4 cylinder/ reg cab . 222k miles

I have recently experienced very slow acceleration and poor power performance. From a stop light, its revs up slow. The gears shift fine, just no balls. Much less power than before.

Right now, the truck is still kind/sorta slow. On a rare occasion, it runs very good. But on a more frequent occasion, it is extremely slow. I feel like its pulling a concrete truck behind it. Uphills are a terrible battle. Pulling an empty trailer is nearly impossible.

I have already done the following:

1. Fuel pressure test checked out
2. Exhaust pressure test checked out
3. Checked all ground point or loose connections
4. Changed MAF
5. Changed TPS
6. Changed Cat recently
7. Changed Crank and camshaft position sensors lately
8. Tested knock sensor resistance. Output good.

I am totally stumped. I could use some advice. Cant keep throwing parts at it.

Kiroshu

-Check spark plug(s) condition for proper torque and specs.
(Loose/worn Plugs = Loss of compression = Loss of power.)

-Air filter dirty...?

-Engine oil low...?

-Excessive drag on the engine...?
(Engine Accessories failing.)
(Resistance in Brakes.)

Variable Valve Timing Components Intermediate Fault...?

Any trouble codes...?

usadaytrader

Replaced with Denso plus 20k ago.
Air filter brand new
Engine oil good.
Rear brakes not dragging
VVT timing controller replaced 3k ago after putting up a light
No engine codes.

I am completely stumped.

85sr5excab

When's the last time u changed the fuel filter? That's what it sounds like to me.

usadaytrader

Fuel Filter is in the tank. I could have a volume problem, but I haven't tested it yet. I highly doubt it tho.

Greg_Canada

Maybe someone swapped a 22r in there?

usadaytrader

Damn Gremlins

crazypaint

Ever run seafoam thro it. Put it in ur gas tank on fill up

usadaytrader

Yup. Did both Techron and Seafoam through gas tank lately. Ran seafoam through brake booster vacuum hose as well. No change

Kiroshu

Did you verify torque..? <--- "Check and see if they are tight."

usadaytrader

I torque to spec bro. Have 5 different torque wrenchs cause I am anal like that. ft-lbs and a a variety of inch-lbs

Kiroshu

Sweet just checking.

I'm the same exact way. Very very anal with attention to detail.

Kiroshu

Noticed any unusual noises associated with your drivability issues...?

-Check alternator out-put..?

Greg_Canada

Have you ever replaced the o2 sensors?

usadaytrader

I changed the brushes on the alternator. I tested the charging system with and without load. Its all good. I replaced both O2 sensors when I did the cat at 172k.

Greg_Canada

Have you checked your TPS to make sure it is within spec? I see you changed it, but it may need to be adjusted.

How dirty is your intake, lots of gunk built up?

usadaytrader

Throttlebody cleaned. TPS is not adjustable. Sealed and part of the TP assembly.

Kiroshu

Sounds like you have taken some very professional steps and quality care for your engine.

Something is still amiss...

Assuming the engine is completely healthy...

Something is relinquishing the engines power...

Is your truck equipped with Traction Control...?

A malfunctioning Traction Control Module could be inhibiting the engines performance.

250000_yota

You said the vvt-I controller was replaced, do you mean the oil control valve or the actuator on the end of the cam? Also, if the control valve was replaced, was the valve cover removed to clean the ports that feed oil to the control valve? If it was the actuator that was replaced, are you sure you got the timing correct when the chain was re-installed?

How about a compression test and leak down? Just to be sure...

250000_yota

Also, what trans is behind the motor? I'm assuming it is a manual. Haven't seen many of these trucks with automatics.