Vacuum Hose Collapsed.

My truck is old, over 200,000 miles, but it doesn't miss and it doesn't smoke. I have a 1999 F150 4x4 XLT and have loved it since 99.

Lately it had been starving as I climb hills and has just seemed to have no real power.

I am a fairly analytical guy, an electrical engineer. I build ships and understand a lot of things mechanical. I use to work on cars a lot in the 70s and 80s, hotrods. Since the late 80s I have been buying new and just started to have everything done for me in regard to repairs.

Well short story Long... I tried all the troubleshooting and web searching I could to find out what is wrong with my truck. To be honest, most of the things that rob power had a whole lot of other problems... Missing, wasting fuel, over heating etc. I didn't have any of that. I read about EGRs, plugged ports, PCVs etc and that was the direction I was leaning. To start off with the cheapest and easiest I thought I would just replace the fuel filter. My filter was old and ugly, but that didn't fix it.

Next I replaced my PCV I took it out and looked at it. It shook and made the rattle sounds, not plugged or frozen up. The part was only $2 so no big deal. I didn't think that would do it. I drove the car and it ran better and it puzzled me so I looked under the hood for other things. The hose from the PCV had come off of the intake manifold when I changed the PCV. So I plugged it back in and it ran bad, starving for fuel, struggling up hill, just acted like it was starving. I read and read ECRs, sensor etc and one fellow mentioned a leaky hose. He said he fixed his problem (dealer wanted over $500 to replace his EGR and the sensor. He said the $3.00 hose fixed it. So it was just getting dark and I thought I would look at my hoses. I found two elbow shaped hoses coming from the PCV to a tee and then to the manifold completely collapsed. I ran to the Auto Zone and got both those pieces of tubing for $10.00. I thought that was a bit high, but I had to do it. I put them on and my car runs good again. It still needs to be tuned up by the mileage, but the truck runs great, lots of power. Apparently Oil from the PCV broke down the hose/tubing and sucked it closed from the manifold. It was starving for air. It is funny I never seen them before, but I thought it was something bigger.

It was so strange that my truck ran better with the vacuum leak. It needed that air from the PCV to run right.

 

You got the wrong PCV these engine are picky about some parts the PVC is one. Look at your old PCV it should have extra holes the aftermarket cheapos dont that allow the engine to breath better, The elbow rotting out is also common. Get a Motorcraft PCV.. Didnt you get a check engine light in all this? are you using oil?

 

Let me tell you that the truck runs on complex computer software that you seem not awhere of but now finding out.
The crank case is a closed system.
If blocked or unaccounted for air is leaking in, it shifts the fuel tables in software trying to self correct the condition.
The OX sensors detect the condition and feed back the change to the PCM.
If the tables are shifted far enough it causes codes to be set and the CEL light to come on.
These codes tell you what happened to the software not the hardware directly even though the hardware caused it.
Your just beginning to get into all this unless you trade for a new truck .
Then your starting all over again with a newer more complex version of the operating system.
Good luck.

 

Well the PCV valve that I bought looked very similar to the replacement, it runs well now, and that is with 100k on the spark plugs.

I never looked at any codes and I am just learning about them now. Although I am an engineer, I never studied any of the higher tech mechanics of the last 20 years. I suppose it is time for me to devote a part of my brain to cars.

The thing that got me is that what was happening to my truck was happening to the whole engine and not a single cylinder. Most of the troubleshooting guides didn't cover this. Most component failures caused missing, bad fuel economy and over heating. All my engine did was starve and my initial reaction was in replacing the fuel and air filters.

Thanks for the help. I hope this thread may help others.

 

I don't see myself buying a new truck anytime soon, although I would love it. I have a couple dents in my box, the seats are coming apart, but I cannot justify the expense of a new truck right now. It has been my daily driver since 1999. I joked when I first bought it that I paid so much they would have to bury me in it. That may be true. Next week I am going to put new tires and shocks on it. I wish I could just go buy a couple of bucket seats. All I find when I search or seat covers. In a couple of weeks I will tackle spark plug replacement. I plan to take off the EGR and clean it, replace some more old hoses, replace the coolant etc. Just get it ready for a couple more years of abuse. I am either lucky or this truck was meant to take a beating.

 

Yep....genuine motorcraft for the pcv system....

 

100%!, -Specially that little PCV valve. ONLY the Motorcraft part has the correct margins. So many blow that off, = early grave. Important little part, -if your after longevity.