View Full Version : Truck running terrible. Need help...

07-02-2007, 09:56 PM
I have a 1997 Mercury Mountaineer with 5.0 V8 engine. I noticed lately it's been hard to start and now it's skipping really bad until it warms up. I started listening to the engine yesterday and noticed a hissing sound such as a vaccuum leak. In the first picture, there is a metal fitting where it looks like a hose belongs but I do not a loose hose anywhere nor do I see where the other end of the hose would connect to. When I put my finger over the hole it'has a vaccuum on it and it will shut the engine down if my finger is kept over the hole This area is just under the right side of the intake manifold area (2nd pic). If you have an engine the same size and approximate year, please advise me what's causing this. Thanks in advance.

07-03-2007, 09:55 AM
Bump Bump Bump

07-03-2007, 11:31 AM
Sorry, Not much help on this one. I got out of the auto biz 16yrs. ago, I hope you don't mind but I posted this thread in a auto forum I'm a member of. I will let you know should I find anything out.

07-03-2007, 12:02 PM
I don't mind at all. Thanks.

07-06-2007, 06:58 PM
I don't know if you got it fixed yet but this just came in today;

On my 2000 Mountaineer with the 5.0L, that port points toward the firewall. There is a rubber hose attached to it and, just at the rear of the upper intake, there is a plastic right angle connector and it runs behind the intake over to maybe the PCV? From the service manual, it appears they refer to the connector in question and the one like it towards the front of the manifold as the PCV heater ports.

If your Mountaineer still has the vacuum diagram on the hood or core support, you may want to check that and see what it would indicate. My Mountaineer has a new hood and core support, so I no longer have the vacuum diagram.


Bill M
07-07-2007, 12:05 AM
Check for a loose hose, if you can't one, cap it off. Check if the pcv on the rear of the lower intake is plugged in.

Vacuum sources to check
- pcv
- brake booster
- carbon cannister
- fuel pressure regulator
- vacuum tree on fire wall

take a good look around, even under the front of the upper intake for a hose that is open. Don't be afraid to pull on the hoses slightly.