Help!

[Dahlonega]

I'm experiencing power loss in my 1999 2wd Toyota 4runner with 140,000 on it (it's a California car too). The truck struggles to make it up hills and is slower than a snail from a stop. I occasionally get a blinking check engine light, but it doesn't stay on for long. And when I put it on a code reader, there is nothing stored (this was with my cheapo reader and a shop "tech two" reader).

Here's what has been checked or replaced so far: plug wires, plugs, air filter, fuel filter, timing, fuel/oil pressure, and mass air flow sensor. The timing belt was changed about 20,000 back. I ran STP fuel system cleaner and injector cleaner through it. I also removed the second catalytic converter to test if it was clogged; the truck got loud but didn't perform any better.

I took it to a shop I've used before and trust and although they could feel the power loss, they were unable to find anything going on.

I can't afford another car or dealership fees. I'm hoping someone can help me out here. Any ideas? Any recommendations for shops in the north Georgia/Atlanta area?

 

[4Running Daily]

Does it shake at all at power loss?

Any smoke that was noticeable from tail pipe?

Coolant Loss?

Oil loss?

 

[Dahlonega]

No shaking, smoke, or oil loss. Coolant is fine too. The truck doesn't run rough while idling or under load.

 

[Suprareal]

is this a 4 or 6 cylinder?

 

[Dahlonega]

6 cylinder

 

[4Running Daily]

What happens exactly when you straight up nail the throttle off of a stop?

Revs high but doesn't go anywhere?

Just slugs?

 

[Dahlonega]

It revs but doesn't redline. I stopped on a gravel road on a slight incline and couldn't spin out. It really just feels like I'm towing a boat behind me. Same exact feeling.

 

[4Running Daily]

Try changing your rear diff fluid to something of lower weight.

 

[Dahlonega]

How would rear differential fluid cause the check engine light to flash?

 

[theizzardking]

o2 sensors checking out ok? if these haven't been checked i'd look in to..they can cause performance loss without throwing a code...
4x4Wire - Tech: Time to Replace the O2 Sensor on your 3rd Gen Toyota?

After doing some extensive reading, it began to come clear how the O2 Sensor performance could be off, yet not be able to see any symptoms (other than lower gas mileage) with the tools I was using. It turns out that the O2 swing cycle shown in the photographs is the swing time of the overall system and not just the O2 sensor itself. To really examine the performance the O2 sensor, for example to determine if it was developing a lean or rich offset, one would have to use a digital volt meter with an averaging feature connected directly to the sensor and look for the 450mV centerline signal in a known, properly performing system centered at the 50% duty cycle. To measure responsiveness, one would have to use a laboratory scope and setup specifically for this measurement as a properly performing O2 sensor has response times in the neighborhood of a few hundreds of a second, not the average 1.8 seconds seen as the overall system response time by an OBDII scanner.

So when do you replace the O2 sensor? The answer turns out to be simple. Per a trusted Toyota service manager's experience and, experiences posted in the Toyota 4x4wire Forum, the O2 sensor needs to be replaced on average every 75,000 miles to maintain optimum gas mileage performance.

 

[theizzardking]

How would rear differential fluid cause the check engine light to flash?

oh the lights flashing, 02 sensor maybe, possibly a bad injector?

 

[4Running Daily]

I've seen it happen before. The engine is working so hard to spin the diff that it flashes a check engine light. It would be a lot more sluggish then what you are describing. O2 sensors are a possibility.

 

[Dahlonega]

The CEL has flashed 3 times in the past couple of months; the first time was right before I noticed power loss. I had an O2 sensor replaced about a year ago when my check engine light was on steady, not flashing. I would imagine this could be the problem, but the shop I took the truck to is good enough to check that type of thing out. They said none of the cylinders seemed any different from the others. Timing was dead on too.

 

[4Running Daily]

I recently had an injector go out. My CEL flashed like crazy. That is why I asked about shaking. When an injector goes bad, the truck runs rough and shakes like crazy.

 

[madbomber08]

I know it wouldn't produce a CEL, but is your throttle cable nice and tight?

 

[Brutus]

How's your e-brake? It's not rusted up or messed up somehow, is it?

 

[Dahlonega]

It looked tight to me. I'm guessing the shop checked for that too.

 

[LittleCaesar]

Any trouble starting it? How long has this been happening?

Who did the timing belt change?

With the CEL occurring intermittently, I'd suspect that the problem is with the engine. Possibly timing. I'd do a compression test first, and see what readings occur. Then you can decide whether the problem is internal of the engine or external.

Also make sure your crank bolt is nice and tight. 217ft/lb and no less.

 

[Dahlonega]

The timing is dead set. There is compression in all 6 cylinders.

 

[20034RunnerV84x2]

Go to ToyoTechs in Atlanta. Great shop, truthful, honest, and does great work. Highly recommend then!