Hello Folks,

I have a 2000 F-150 with a 4.6 V8 with approx. 35000 miles on a rebuilt engine. The thing seems to have no pep to it. It hesitates during acceleration and I don't even want to try towing my RV with it.



The computer has thrown no codes;



A vacuum check shows it running about 18.5 pounds of vacuum. When revving the engine, the needle drops to 0 and then shoots up to about 22# before returning to 18.5;



I tested the vacuum lines by using an UNLIT propane torch all along the vacuum lines with the engine running with no change in the idle;



Where do I go from here?

Thanks,

Chuck

 

#1 it's a 4.6, obviously it feels like it lacks power

#2 obviously without a power adder it won't make boost

#3 when is the last time you did any maintenance / what was done / what parts were used???

 

Go to a muffler shop and get the cats and the rest of the exhaust system tested for blockage.

 

#1 It has had a lot more power in the past;

#2 What is a "power adder"?

#3 Replaced plugs, used autolite double platnums. Replaced two COP's, swapped around the rest of them with no apparent change in idle.

Thanks!

 

Great suggestion! Do you know how they test these systems?

 

a power adder that would add boost is a supercharger or turbocharger


you're running plugs that are known and proven to be useless in your truck might want to change them to some motorcrafts


I agree with having the cats tested if the plug change doesn't help the "power" department

 

I think they pull the front O2's and hook up a pressure gauge. I also think they can do it with an infrared temperature sensor.