# toyota tacoma loss of power



## southernboy2147 (Jan 12, 2014)

i have lost about 50% of the power in my truck. seems that the higher the RPM the more power that is lost. ever now and again a check engine light will come on and it will run like crap, like it needs a tune up. theres 5 codes that read when this happens 3 mass air flow sensor codes, the pcv system, and a 02 sensor. 

most of the time there is no check engine light and again an extreme loss of power. i replaced the MAF sensor but that didnt solve it. the pcv system would mean vacuum leak right? i done a check for those and didnt find any. i dont believe a 02 sensor would cause this issue... or would it?

 it does idel at different rpms all the time. from 1200 to 3500, not jumping just sitting there at the RPM.

 idk what else to really do other than take it to a shop which i dont really want to do. can any of yall make sense about this?


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## Eudora (Jan 12, 2014)

Possibly a catalytic converter clog?   Exhaust gases may not be able to escape out the rear of the exhaust system (O2 sensor code) so the engine dies because no air is coming in to form the necessary fuel/air mixture (flow sensor codes).  Just guessing, but sometimes a temp test with a laser type thermometer can diagnose this by taking reading before and after it. A properly working converter will usually run about 100 degrees hotter behind the converter than the pipe leading into it since the converter's job is to use the metals inside to get very hot and burn excess gas off.  Carbon can build up inside it and cause the restriction.  Just a hunch.


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## tr21 (Jan 12, 2014)

my neighbors Tacoma wouldn't even start. wound up being the radio noise suppressor thing under the dist. cap.  you might try that it was only $5 . we removed it and it started up. ran a little rough so I asked him if he wanted me to order him one? he told me it was running without it and it's the trans. making it run bad, I gave up. you might try that it's cheap enough.


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## Old Winchesters (Jan 13, 2014)

Maybe cam position sensor....your best bet is get it checked out.


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## Gaducker (Jan 13, 2014)

The o2 sensor can most certainly cause your problem,  when you have a failing 02 sensor its feed back to the pcm is incorrect and then you use more pedal to try and make your truck go down the road, the longer you use more pedal the worse the condition becomes because the pcm is recieving 100 % throttle position from the TPS and the MAF sensor is only picking up 50 % air flow then all it can do is trip a maf code,  Just because you have codes stored in the pcm dose not mean you have a bad part, Its just a direct result of other problems you have.  

    Thats why you cant take back electrical parts at the parts house because they know parts swappers will do just that, swap parts until they hit on the actual problem.

        I have on more than one occasion found o2 sensors to be the only thing wrong with a vehicle that has had a laundry list of codes in them and they would almost refuse to run down the road,  They would idle but not worth a crap. Look at STFT and compare it to some known good numbers either from a buddys truck or the www.


Toyotas are good about letting you know if the converter is bad and it actually be a bad converter, with out a po420 or 430 code I would not suspect the converter.   to check for a cloged converter just remove your upsream air fuel ratio sensor, or to some the up stream o2sensor.


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## rjcruiser (Jan 13, 2014)

I agree with the cat converter possibility.  Had a buddy in college have something similar happen to his Honda Accord.  After driving a bit, he looked at his catalytic and it was glowing red.  Let it cool down, then took it off...drilled a bunch of holes through the honeycomb insides...took the insides out, re-attached and didn't have anymore issues.

What year...what engine...mileage?

Not sure...but it almost sounds as if your timing is off.


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