Lost power

I have an 04 TRD with the V6 and a 5 speed. The truck seems to loose power and almost bog down at wide open throttle. You can let off the throttle to around 3/4s or half and can notice a improvement in acceleration. I’ve changed the fuel filter recently with no real improvement. Looking for suggestions. The truck has 147,000 miles.

 

Check engine light? Look for codes via OBD2 port?

 

Forgot to mention, no check engine light. Will it have a code with no check engine light?

 

Oxygen sensors, catalytic converters, maf.
Have all of these been determined to be good?

 

Wouldn’t those cause a check engine light?

 

Dry rotted vacuum lines, maybe

 

Typically, yes. But sometimes no.
Any alternator issues on it

 

No alternator issues.

 

Fuel pump?

 

A converter (or even a muffler) that is in the process of clogging through interior decay can clog the exhaust stream and deteriorate high load performance quickly.

Sometimes tapping on those will cause a rattle that gives you a hint.

If it is one of those the condition will worsen until it won't run at all. Could be gradual, could be sudden.

 

No issues cranking or idling, no missing or hiccups

 

Except..... loss of power at high rpm, correct?

 

Yes

 

You can have codes with no check engine light. Worth checking.

 

Only at full throttle. If you only give it around 3/4 throttle it will accelerate like it should just seems to bog down when at full throttle.

 

Will have it checked for codes on Monday

 

Ok. Start reading.
https://www.google.com/search?q=pow...azARoQrQIoBHoECAoQBQ&biw=412&bih=756&dpr=2.63

 

Thanks

 

My first two guesses are you throttle position sensor is faulty and is giving the wrong signal at peddle full down or you don't have sufficient fuel pressure.

Best of luck.

 

Thanks