Out of the blue a few days ago, my truck suddenly has zero accelleration. ZERO. You give it gas, even floor it, and it bogs (no sputters or misses) and makes a hollow sound, eventually it gets moving enough, but it's got no power. No check engine light, engine idles fine. When it FINALLY gets up to highway speed, it cruises fine on level ground, if it hits a hill, it's OVER, downshifts a couple times and cannot maintain speed.

Any idea about where to even start on this? I changed the fuel filter and plugs within the past year. And 2 bad O2 sensors in May (triggered check engine light)

Sounds like it is starving for air or fuel, but engine never misses or sputters, and idles fine...

 

Blocked air intake or plugged exhaust.

Check the airbox (air filter housing), I've heard where insulation can get sucked into it. Go to a muffler shop and get the exhaust checked for blockage, it could be plugged converters or collapsed muffler baffles.

 

Or very low fuel pressure

 

I would think low fuel pressure would have throw a code, isnt there a pressure sensor somewhere?

Speaking of exhaust, the exhaust smells like it's running REAL rich

 

2005 5.4? You may have the leaky injectors, which are plugging your cats. If you have less than 120k on it get it to the dealer. If more than 120k, you may be in for a substantial bill.

 

I agree with GLC. Raw fuel leaking from an injector is burned at the catalyst and can often melt it effectively reducing the amount of exhaust that can pass through it. If the exhaust can't get out fast enough a loss of power results. This problem will only get worse and not better. Also if the injector leak fills up the cylinder with fuel a hydrolock can occur causing rod and piston damage. Take it to the dealer.

 

It's a 4.2 v6, not a 5.4

 

Check the fuel pressure.

 

Even the 4.2 that year used a FPDM, the only way to test fuel pressure is with a scanner that can read out the PID. No test port on the rail.

Take it to a muffler shop and get the exhaust system tested for blockage.

 

Just out of curiosity, how will they check for blockage? Do they have to pull the exhaust manifold?

 

No, they can use an infrared scanner and/or pull an O2 and hook up a backpressure gauge.