Question about Cars & Trucks

1 Answer

2000 Mercury Mountaineer 5.0 Vapor Locking?

2000 Mountaineer 5.0L. Truck runs great at 126,000 until the air temp. gets above 95 degrees and I run for a 30 to 100 mile trip. the merc. will jerk-get gas not get gas something like a clogged fuel filter but not. ive owned a carburated vehicle that has vapor locked and know the feel. EFI vapor lock? everyone ive talked to says no way. HELP PLEASE!

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.


    An expert that got 20 achievements.


    An expert that got 10 achievements.

  • Cars & Trucks Master
  • 42,218 Answers

Maybe what you have is not vapour lock as such but a vacuum forming in the tank and not allowing the fuel to be pumped to the injectors. I would be checking the canister and canister controls to ensure adequate venting. I f the fuel tank has been continuously filled to the filler neck then fuel can contaminate the canister and not allow it to work properly. In short I would be looking for reasons in that area Run fault code check and see if any fuel related problems are presented.

Posted on Jul 17, 2013


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

We have a toyota 2000 camry which stalls after long distance driving. we have replaced the cool and temp sensor and found the air flow box wasn't connected. it is now and still stalls

Do you live in a hot climate? I have not heard this happen on newer cars but it sounds to me it is vapor locking.check and see if the gas lines run by anything that gets very hot. I worked a 2005 ford truck that was doing the same thing. I had to run the gas lines on the other side of the frame. Good luck

Apr 05, 2017 | Toyota Cars & Trucks

1 Answer

2009 Mercury Mountaineer, my heater wont work unless I'm driving and get over 50 mph... I let my car warm up for 20-30 minutes and it wont defrost my windshield, it only blows cold air.

i would check the thermostat,i think its stuck open the coolant is running cold so you should install a new thermostat with higher degree.

Jan 13, 2015 | 2009 Mercury Mountaineer

1 Answer

1997 nisssan pickup 4 cyl. 5 speed. Truck runs fine at all speeds until the engine gets really hot (outside temp 100+ degrees), then engine sputters and will not take gas. Acts like old cars that had...

There may be more specific solutions along shortly, but my older car had similar problems until I changed the ignition module. The "spark box" as it was nicknamed. My car was a mustang, but it only seemed to act up on hot days, and if I just pulled over and allowed the car to cool for a bit it would go again just fine. I'm not familiar with Nissan trucks specifically, but it's another place to consider. Good luck!

Aug 14, 2011 | 1997 Nissan Pickup

1 Answer

2000 mountaineer

chilton or hayes make a great book for your truck with pics diagrams and full instructions on how to do a tear down

Jan 10, 2010 | 2000 Mercury Mountaineer

1 Answer

1995 jeep cherokee dies after driving for more than 25 or 30 min acts like it is vapor locked also temperature gets to 190 on thermostat within a couple of minutes of starting the car after setting...

Most run at 200-210 degrees so the temp you stated is fairly normal....Vapor lock generally is associated with mechanical pumps that put out 5-8lbs of pressure...the electric pump in your car puts out over 40 when needed and unless you're running in the desert, it's doubtful that it's locking.You need to do some testing to determine exactly what pressures you have at the fuel rail, if you are getting good spark etc. in order to determine what's going on there. Don't work blind...get a manual like chiltons or haynes that can give you specifications and test procedures...It's cheaper in the long run than just throwing parts at it 'till the problem goes away!!! If the engine is balky or slow turning the problem may not be fuel or ignition but may turn out ot be a worn out starter...That's why testing is so important!!! If you have any questions about any specific tests, don't hesitate to ask. Good Luck!!!!

Jul 08, 2009 | 2000 Jeep Grand Cherokee

1 Answer

O2 mountaineer

You didn't say whether your engine is a 4.0L v6 or a 4.6L v8 but if you have an excessive amount of air blowing back into air box and vehicle is running good otherwise you may have a stuck open PCV valve causing it to pull to much vapors from engine crankcase.
If it is a 4.6L it will be located in the valve cover itself.
If it is the 4.0L locate the hose coming off of the back of the upper intake and it will be at the end of this hose. This one you twist CC to remove.

Feb 25, 2009 | 2002 Mercury Mountaineer

1 Answer

The 2000 mountianeer starts and runs fine but shuts off


Jan 24, 2009 | 2000 Mercury Mountaineer

1 Answer

Runs rough when below 35 degrees


Dec 30, 2008 | 1988 Dodge B250

2 Answers

Engine stalling

ignition control module shuts car off when gets hot and will start after it cools on a 94 its under coilpack easy fix

Jul 22, 2008 | 1994 Oldsmobile Ninety Eight

2 Answers

2002 Outback air condistioning

Look at your fan. You either have a weak fan clutch or if its electric you have an electrical fan problem. You need to see if the fan is running strong when it overheats. I am assuming you have checked your coolant.

Jul 10, 2008 | 2002 Subaru Outback

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

104 people viewed this question

Ask a Question

Usually answered in minutes!

Top Cars & Trucks Experts


Level 3 Expert

75842 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22156 Answers

Randy Ohler

Level 3 Expert

14585 Answers

Are you a Car and Truck Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides