Guys I'm at my wit's end!!! I need help, seriously!!! My 95 f150 5.0 has NO power! It's at the point that it's not safe to drive and it's my D.D.! The motor runs like a top (replaced 3500 miles ago) the timing is set at 10° before TDC, and it has a new tps. I thought maybe it was the catalytic converter, but there is plenty of flow coming out of the tail pipe, but it's so hot you can't keep your hand back there. Coming home from work I drove over the same bridge I always drive over. I was doing 45 mph when I started the incline by the time I got to the top I was going 13 mph!!! I had it floored the WHOLE TIME!!!

 

Get a vacuum gauge and hook it to a main port from the intake. Check vacuum at idle over several minutes. It should be 18-20 and steady. Next rev the engine to around 1500 rpm and keep an eye on the gauge for several minutes. It should stay steady. Any steady drop off at idle or high rpms will indicate a plugged cat. That's where I would look first.

Also, hook up the gauge and watch it when the engine is first started. If it starts out 15 or less, I would suspect a bad timing gear that has let the timing slip a notch. How does the engine start when cold? Any changes from before this started?

 

Ive had similar symptoms when the truck I was driving had non functioning in tank fuel pumps. Ran fine when doing it easy but on a hill etc it would start to struggle.

 

One thing I forgot to mention. Its drinking tons of gas and I've noticed when I first put gas in it or any kind of fuel system cleaner it runs great for maybe a mile then no power again.

 

Sounds like weak fuel pressure. Check it with a gauge.

 

What should it be?

 

Fuel system should make 32-35psi with engine at idle and 40-45psi with vacuum removed from the regulator. And pressure should never drop below the idleing value when the engine is running and the system should hold this pressure when the engine is shut off. If your truck fails on any one of those factors report back for a diagnosis, you could have a weak fuel pump or a stuck open injector or the fuel crossflow problem if the truck has dual tanks.

 

It has dual tanks. I'll check it and let ya know

 

At idle it's 32 and with the vacuum off the regulator it's 41

 

When motor is off pressure stays at 40

 

Rev it with the gauge hooked up and see what it does

 

Years ago i had a bronco with the same issue... guy at ford said to check the muffler! I went away thinking how stupid is he, a month later i had it in at a shop and after the mechanic went through everything he disconnected the muffler... problem solved. I had lots of exhaust coming through i thought, but under load there wasn't.

 

Reved up the psi goes to 30

 

And there ya go. You either have weak pumps or a clogged fuel filter

 

What psi should it be when reved up?