2000 Mercury Mystique

Welcome to my web page dedicated to my new car. This car is the successor to my favorite car, my 1984 Mercury Topaz.

The Story

I decided it was time to get rid of the 1984 Mercury Topaz at last. It had been leaking steering fluid like crazy. So we went to the dealer, and spotted this blue 2000 Mystique that was reminiscent of the 1984 Topaz color. Unfortunately, it was a 6 cyl automatic. Talk about a crowded engine compartment. Not a big plus for someone who does their own repairs. But I decided I'd get it anyways since ordering what I wanted would probably be a huge hassle, and dealing with the leaky Topaz was really getting old.

The car has about 738 miles as I'm writing this, so there isn't much more to tell. I'm sure this will change with time. In the meantime, several exciting things have happened. Keep reading...

Caliper Pins

The caliper pins are easy to remove/install on this car. They clean up nicely with kerosene. Perhaps a little steel wool if you really want to remove the brake dust on the end. Dry thoroughly, apply caliper pin grease, and re-install.


I did my first drum brake job ever on this car. It was a little bit of an adventure, but I was successful. The parking brake cable was a bit tough to figure out. On one side, the adjuster arm wouldn't come off the shoe. Had to pry against the spring, insert screwdrivers into the spring, then the spring was loose enough to separate the parts. Putting the spring clips back on was painful. Then the final drum wouldn't go back on. I was way too fatigued at this point to notice that the shoes were terribly askew. Took a break, and realized what was wrong. Of course, the old pads had plenty of life left in them (at 75,000 miles), but I went ahead and did the job anyway since I was in there.

Brake Job 3/20/2010 Notes

Shop Manuals

Received the shop manuals for the car 3/28/2006. Ordered them online from Helm. Cost about $300 for the Mystique manual and the 2000 powertrain manual which covers all models. Very cool stuff. Now I know what that box under the water pump pulley cover on the front of the 6 cylinder engine is. I had to remove it in order to replace the spark plugs. Turns out it is the Intake Manifold Runner Control (IMRC) actuator. When the engine goes over 3000 RPMs, the IMRC actuator kicks on, pulling on the IMRC cable and opening up extra channels in the intake manifold to allow more air in. In this way it tunes the intake manifold for more appropriate airflow above and below 3000 RPMs.

Spark Plugs

Summary: Replace the plugs and wires every 50,000 miles on this car and use only Motorcraft parts.

Like a dummy, I kept putting off the changing of the spark plugs until 68,004 miles had gone by. Then, the car wouldn't start. Cranked fine, just wouldn't start. The last thing I had done was to drive about 100 feet from outside into the garage. I guess that short trip finally pushed the plugs over the edge. I managed to start the car the next day after puzzling overnight over what the problem might be (duh!). It ran incredibly rough and sprayed gas out the tailpipe. It was like it was missing two cylinders, which it probably was. The spark plugs fire in pairs on these engines, so if one goes, it's the christmas tree light effect: The other plug connected to that ignition coil goes as well. I took the spraying gas to mean that the fuel pump was indeed fine, and I needed to take a look at the ignition system.

Replacing the plugs and wires was surprisingly easy on this car. I took two days to do it, just so I could be extra careful and not mess anything up. The main annoyance was the fact that the replacement wires I got were not exactly the right length. They were a little too long. So I had to get creative and find a place to store the slack. I decided to move all the slack toward plugs 4, 5, and 6, and stow the extra cable under the water pump pulley cover. This seemed to work fine for a while, but 15,000 miles or so later, I started having ignition-related problems. I think I'm going to try a set of Motorcraft wires soon and see how that goes.

I also learned that Bosch Platinum plugs, although they say they are "pre-gapped", still need to be gapped as they only come in a small selection of gap sizes. The ones they gave me were gapped at .044, while the V6 Mystique wants .054 (see the emissions decal under the hood to verify). If you tear apart the box for a four pack of Bosch Plugs, it explains this.

Warning: The Bosch Platinum plugs appeared to have failed after about 15,000 miles. Specifically cylinder 2 (in bank 1, read on) was misfiring. According to the dealer, they've seen problems with Bosch Platinum plugs in this car. Not sure whether I believe it, but they work on these things all the time. Had them switched for Motocraft plugs, and all appeared to be fine. The symptom was misfiring at idle and up to 2000RPMs in neutral.

Of course it may have been the aftermarket wires. A few thousand miles after they replaced the plugs, I started getting a P1131 diagnostic trouble code (DTC) from the computer. This means the upstream (of the catalytic converter) O2 sensor in bank 1 (cylinders 1,2,3 near the back) isn't switching due to a lean condition. I used my CarChip to monitor the O2 sensor in question and sure enough at idle I was seeing the O2 sensor stop switching. While it was idling I played with the #1/2/3 plug wires, unkinking them, and the problem went away. So, I think from now on I am definitely going with the manufacturer's ignition parts.

9/28/2014 Update: Finally made it to 130,000 miles, almost. Changing the plugs and wires due to the P0430 trouble code. Emissions are due for me 11/5, so I'm trying a few things to clear the code. Using the Motorcraft wires this time. They are indeed much better than the aftermarket ones that were in there. The Motorcraft wires have clips on the connectors on the coil side to make sure they stay on tightly. This should improve contact. The key issue I ran into this time was pulling the plug wires off the plugs. Numbers 1, 2, and 3 (in the back) are pretty hard to get off. However, I found that the angle-bracket style boot puller helps a bit:

Just dig it in as best as you can and start pulling. It will come loose. Plug #3 wasn't so easy. Had to just yank on the wire. It worked.

Plug #4 was a little tough to thread in. Not sure if there's dirt in there or what. Didn't feel like cross-threading as I was able to finger tighten it for a turn or two. I used a torque wrench for a change, so in theory it should be in there tight enough.

Had a problem with the spark plug socket sticking on the plug so much that the extension pulled off the socket leaving the socket down in the tube. Solution: put a little spark plug grease on the porcelain insulator before putting the new plug in the socket. Then it slips right off. I still had to use locking extensions. A socket with a built-in extension would be even better.

Fuel Pump

The fuel pump died gradually on this car. I'm not sure whether the damaged fuel supply line had anything to do with it (perhaps causing the fuel pump to work harder than normal). As the fuel pump problem progressed, the car would be more sensitive to how full the fuel tank was. Toward the end, you couldn't let the tank get below one quarter (1/4) before the engine would stop running. Replaced the fuel pump and the supply line, and all was well.

Got an email from Russell Fry saying he thought he was having similar problems. He sent the following nice photo of the fuel pump under the back seat on his 4-cyl 2000 Mystique.

Replacing it turned out to be too much for him, so he had the dealer do it. Unfortunately, that wasn't his problem. Turns out it was missing teeth on the timing belt. The dealer also replaced a pulley or two. He's back on the road...

Idle Air Control Hum

Another Mystique owner contacted me to thank me for my write-up below on the Idle Air Control "Hum" problem. It apparently was exactly the same problem he was having. He told the mechanic to replace it, and the problem went away. See the "Log" section below for details. Also see this Mystique owner's video. That sure sounds familiar to me.

P0420 and P0430

I've been having the dreaded P0430 "Catalyst System Efficiency Below Threshold Bank 2" code for a while, on and off. It's pretty solid now. Not burning any oil. But the aftermarket plug wires have always been suspect. I used to be able to get it to go off by driving around and making multiple short stops (at stores). That seemed to clear it up at first. Not anymore.

It turns out that the EPA regulations allow a car to pass emissions even if it has one or two (depending on model year) unset readiness codes. Maryland appears to honor this. I assume the rationale here is that some folks may never drive at 55MPH for prolonged periods of time (e.g. city dwellers), so the CAT test may never complete. And this is ok. They aren't going to force them to go out and drive on the highway from cold start 6 times. That would be absurd even for the EPA. And, given that the car isn't used for cruising, the CAT doesn't come into play anyway, so it doesn't matter whether it works.

So, this means that unscrupulous folks can reset their computer, drive the car around a few times, get all the tests except CAT to pass, then take the car in for emissions testing and pass. Although this is directly against the spirit of the laws, there's little the EPA or the states can do about it.

BTW, the Autel MS300 code scanner is fantastic. It's cheap China junk, and it shows the readiness code status in the "I/M" (Inspection/Maintenance) menu.


Rumors were flying in the year 2000 that the Contour/Mystique's days were numbered. In fact, they were. 2000 was the last year for the Contour/Mystique. That left only the Sable in the "mid-size" class from Mercury, and the Taurus for Ford. Then there's the Focus, Escort, and ZX2 from Ford also, but I think these are generally smaller than the Contour. Looks like I'm going to have to go with Japan for the next car.

2000 Mystiques with the 6cyl engine (and perhaps others) were shipped with a loose yellow cap laying between the intake and exhaust manifolds on the left side. I think it was a cap from a hose that was popped during manufacture and left to lay wherever it fell.

Some Specifics

*** Log ***

Note that this log is incomplete. I try very hard to record everything I do to my cars, but occasionally things fall through the cracks. Also note that I am a believer in the Mobil 1 6000 mile oil change interval. Therefore, you'll see oil and filter changes approximately every 6000 miles, although I do stretch this on occasion when life is hectic.

Date Miles Event
4/1/00 000054 Purchased. A little yellow plastic cap was laying on top of the engine when I bought it. They wouldn't give me a discount for that!
4/12/00 000738 Took it to dealer for service. The front left wheel speed sensor bolt is missing (! Quality = Job #1?). I put it back on with a twisty-tie and it works fine. Caused the ABS light to come on when I went over bumps. Shop installed "new" bolt from the bolt box.
6/21/00 003291 Oil.
10/1/01 007252 Oil/Filter.
1/10/01 010215 Handlebar incident. Ran over some handlebars which damaged the fuel supply line. This may have led to the future failure of the fuel pump.
2/10/01 011181 Rotate tires.
3/23/01 012171 Oil/Filter.
3/9/02 022428 Oil/Filter. Rotate Tires.
5/3/02 024551 Replaced rear left tire.
8/12/02 027200 Emissions time! The idiots at the emissions inspection station couldn't figure out how to hook up the OBD II connector, so they only did a gas cap/tank pressure test. Sweet! Looking around I see that OBD II code testers have come down in price significantly. Equus appears to make a decent one that sells for $170. When the time comes, it looks like this will be a pretty painless thing to do....
11/4/02 0????? Groaning under the hood. Idle Air Control valve starting to fail. Coolant light was also coming on due to cold weather, and the coolant being a little on the low side.
11/9/02 030456 Oil/Filter.
12/2/02 031149 Air filter. Engine moaned to the point of stalling. It was cold outside.
12/4/02 031??? Around the beginning of November, a loud moaning noise started coming from the general area of the transmission (transaxle). It sounded like a tone of constant pitch. It became worse with the cold weather. After suspecting the transaxle, I also noted that the engine coolant light was coming on (even though the recovery tank is at max). This led me to sift through my Haynes manual (don't ever buy a car without one) and find that the water pump is mounted on the transaxle, and if a bearing is blown, it will typically make a howling noise. Since we've still got 5000 miles left on the warranty, they should fix this for free. Thank goodness it wasn't the transaxle. On the 6-cyl Mystique, the water pump is relatively easy to replace. Not so on the 4-cyl. Another strange symptom I was having is that the engine would occassionally hesitate and stall. I assume this is because of the added load of the failing water pump.
12/6/02 031221 Turns out it wasn't "howling", it was "humming". The mechanic was taking the car into the garage to switch out the water pump (at my request) when the sound finally reproduced itself for him. Once he heard it, he knew exactly what it was. Turns out it was the Idle Air Control valve and it was covered under warranty. I must admit that this makes a lot of sense. It sounded like it was air related. The sound was too smooth and the pitch was too constant to be a blown bearing, or a pump run afowl. Plus I did have occassional hesitation and stalling. Apparently, something was stuck in the valve that flapped loose every once in a while (especially in cold weather) and made the idle bypass channel "hum". We tipped the mechanic $50 and got a big thank you over the phone. Always remember to tip your mechanic. On the road again! Update: Check out this video. Sounds really familiar to me.
11/20/03 043335 Oil/Filter.
2/28/04 046545 Blower will only go to full. Resistor pack is blown. At some point in the future, I replaced this. I have no record of this, however.
??/??/04 049742 Oil/Filter.
7/2/04 051776 Tore apart the front brakes only to discover that the Haynes manual printed in 2000 is incorrect. It fails to mention the caliper carrier bracket that must be removed to get the rotors off. The 2004 version does (89ft/lbs torque). However, it still doesn't mention what the compound was that I found on the bracket bolts. The color is tan. I assume it is some sort of locktite or something. I used lock-tite titen on the left side, and the heavy duty red on the right. We'll see which one falls apart first. Overall, the brake job went fine. New pads and rotors installed on the front. Biggest pain was getting the caliper springs back on.
8/28/04 05???? Replaced front left tire. Nail.
11/14/04 055925 Replaced air filter. Cannot let fuel drop below 1/4 tank, or car will hesitate under load. Fuel pump is failing.
11/20/04 056195 Oil/Filter
11/24/04 056231 Dealer: New Fuel Pump and new Fuel Supply Line. Coolant Flush/Fill, Power Steering Flush, Brake Flush, Oil/Filter, New Battery.
5/21/05 062692 Oil/Filter. Cabin Air Filter.
2/9/06 068004 Replaced plugs and wires for the first time. This after the car refused to start, and when it did, it shot gas out the tailpipe along with running VERY rough.

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