Mercury Villager running rough

rough
mercury
villager

#1

I have a 2000 Mercury Villager with 150k miles and it is idling and running very rough.



When I start the van, there is a slight rough idle, but when it warms to normal running temperature, it starts to run very rough. At idle, it chugs and nearly dies and goosing the throttle doesn’t help when I start the car moving. When I’m driving, on the highway, it starts to miss on acceleration. Then I pull off a ramp and it begins really chugging, like it just can’t get going.



The odd think is that it will sometimes right itself and just when I think it’s going to die or backfire, it is suddenly running smoother and will drive along for a bit before it acts up again.



So far, it’s gotten new plugs, wires, a new distributor, and two new catalytic converters. To my horror, the cats did not help the situation on a test drive last night. After installing the distributor, it ran well for about a week and a half before the problem re-emerged.



The only code so far is for the knock sensor.



Anybody got any ideas?


#2

Get the coil(s) tested.
Get the fuel pressure tested.


#3

Just so you’ll know, unless they’re plugged, the cat will rarely have any effect on a drivability problem. I’d first try to see if I there are any pending codes even without a check engine light. Then look at the TPS, MAF sensor, check fuel pressure when it acts up.


#4

To follow up:
Still no codes and fuel pressure checked out. I tested the TPS and MAF as best I could and they appeared okay. I dug around on the net and found that the distributor problem is common for my Villager, so I tore into the old one and was able to verify that it was the source of the problem, originally.

I’d purchased a new dist. from Ebay and opened it up, but it already showed some wear in the short time it’d been on my car. I pretty much took the good parts from the two distributors and rebuilt the one that was installed and voila!

The problem is that I don’t know if I got a bad distributor from the Ebay seller, or if there is something wrong that is causing the distributor to go bad. Any advice?


#5

Thanks for the follow up Tool_gal.

Can you describe in more detail what is wearing out in the distributors?

I would go to a reputable parts store or vendor and get a re-manufactured distributor if your DIY doesn’t hold up.


#6

The first distributor had metal shavings from a worn bearing. Only about half of the ball bearings still exist. So the shaft doesn’t rotate well, lots of metal on metal sound.

On the new distributor, the contacts at the top of the cap had brown marks on them, and there was some wear where the slotted circular disk is read by what I assume is the optical sensor. (sorry I don’t know the correct terminology here) It appeared that the disk wasn’t aligned correctly, so there was wear on the disk and the sensor’s housing.

Some of the original equipment looked a little stouter, so I installed the coil, the sensor and the disk into the new distributor.