Engine skips a beat, 2000 Mercury Mountaineer

[Jared Landcaster]

Two days ago I picked up my 2000 Mercury Mountaineer from the shop. I had my fuel pump and spark plugs replaced. Shortly after taking it home I noticed it skipping a beat, like a very faint jerk? I've still been driving it for the past few days, sometimes it happens every 10 seconds for a few miles and sometimes once every few minutes. Everything I had replaced is under warranty. Any ideas on what the problem could be? Did the shop accidentally do something? Also it has the 4.0 V6 SOHC. Any help appreciated. Thanks!

 

[david4451]

Sounds like momentary fuel starvation, take it back to shop and ask them to check fuel pressure. Should be 65 to 70 psi, also did they change fuel filter?
What brand of fuel pump did they use?
Problems with fuel pump is very very common with replacements.

 

[koda2000]

To me it sounds like it could be that the shop that changed the plugs and wires might have accidentally cracked a spark plug insulator, or even installed a plug wire touching the exhaust manifold and now it's shorting out. I'd take it back to the shop and have them fix it. Do you know what brand and type of spark plugs they installed. Fords are fussy about some brand of plugs. They seem to particularly dislike Bosch and you need to use a minimum of a platinum plug. Double platinum or iridium is even better.

You can try opening the hood at night. Often if you have a cracked insulator, or plug wire shorting out you can see it arcing in the dark.

 

[Spaznaut]

Check all your plug wires and make sure one isn't loose or not all the way seated.