i bought a 93 1.9 Mercury Tracer a week ago and i did some maintence on it (oil,filter, etc) and it was running perfect...until last night. I was in town and i puled into a drive thru, sat for about 10 mins at idle, and when i pulled out n the road again, it was running really rough, had no power hardly, and was burning alot of gas. By listning to the tailpipe it sounds like its missing or skipping. All plug wires,injectors are hooked up good so Im thinking its an O2 sensor. Check engine came on for a few mins then went back off. The guys at Autozone said they cant pull a code unless the light is on, but its off now.

Any suggestions?

 

My dad had a 94 tracer that did the same thing. All of a sudden it would start to miss. It turned out he needed new plug wires.

 

Go back and get the codes pulled. Light on or not unless you reset the computer you are going to have codes set. why guess if you can get put in the right direction .

 

O2 sensor, clogged cat, bad fuel filter, bad fuel pump (or fuel pump relay), plugs and wires, igntion system. This is where I would start, but like Pestco1 said, unless you reset the computer, it should be stored in the car's computer. Hope you get it narrowed down!

 

thanks for the replies. I hope its plug wires rather then a O2 sensor

 

It ain't the o2 sensors.

Check the plugs and wires after getting the codes read.

You can read them yourself on that car with nothing more than a paper clip and your eyes.

Guessing about why a CEL came on is pretty pointless when the computer, with a bit of prodding, will tell you what got it cranky.

Steve

 

Sounds like PLug Wires, I had an 91 Tracer LTS 1.8L ( I think that was the letters, it was the GT model) One day I'm driving and all of a sudden it started missing and farting and no power. Took it to the mechanic because I thought it was more serious, they diagnosed it to the wires. One cylinder stopped firing. New wires and she ran like a champ.
Good Luck,
Brian

 

I agree. One time while changing plugs, I didn't firmly seat a wire. The car was only firing 3 out of its four cyl. Make sure that the boots are seated firmly on your plugs.

 

thanks for the replies.


the boots on the plugs are firmly placed, so its not a loose wire on a plug.
Im thinking plugs and wires might fix it. Hopefully not a O2 sensor

 

Was it raining that evening? I put new plug wires on an Escort one time and it ran fine until it rained. When it rained, the engine would chug like it was missing. I popped the hood at night and it looked like a mini electrical storm around the wires. The wires were arcing off each other. A new set of wires cleared the problem right up.

 

no it wasnt raining--perfect weather outside. I just cant figure out what would make the car go from perfect runnning to skipping/no power just by idling....

Ill give that a try when i go home next...im hoping its not a O2 sensor

 

If it was an O2 sensor, you would have a check engine light glaring you in the face, you would also be running really rich and would smell the gas and see alot of soot coming out of the exhaust. Besides an O2 senor is easily replaced and will be the same cost as wires anyways. Also, when you do the wires, do not go with a cheap brand as they will do the arcing described above in wet weather. I have seen auto part store wires fail more times than I care to remember.
Do not excessively bend the wires and be somewhat gentle with them as they are a wire and can be broken. Use the Ford ones or a very high quality aftermarket set. (I prefer Ford on stock engines, I even use Ford on my 400 HP 1954 F100) Also use some of that spark plug grease, it will help the wires come off of the plugs later.
So don't sweat even if it is an O2 sensor, (if the cel is on and you have a code) they replace easy, I did my tracer in 30 miuntes and that counts jacking it up!
Hope that helps,
Brian

 

Autozone said that they cant get the stock type of O2 sensor and that ill have to order another type that is 4 inches longer than the stock one and that it will need a new wiring harness. The new O2 sensor/wiring harness is $45.99 and i know that a shop will charge 2 hours to install, i think im looking at 150-200 bucks to put a O2 sensor in. How much would new plugs/wires be if i took it to a shop?

 

Well Shop rates typically are 65 an hour. At least one hour for plugs and wires plus parts that are dealer or mechanic priced (overpriced). Honestly, if you have changed plugs on any motor you can do this. Also the O2sensor that autozone is selling you is a universal fit O2 sensor. Don't do that. Just go to Ford and for 65-85 bucks you can have the sensor in your hand. They usually keep them in stock.
But don't buy a sensor until you get that code read that is sititng on your computer. Autozone should do that, otherwise they are morons. Heck even a basic scaner from pepboys that has a blinking light or puts out beeps to dictate code will let you know if it is the O2 sensor. An O2 sensor is easy to replace. Especially on a 4 cyl. try getting the back O2 on a V6 contour. PIA. It is just like replacing a plug in the cylinder head, so don't worry about how hard it is going to be because it is not.

Brian
PS: If you were in The Los Angeles area I'd help you out.

 

plugs look easy except the end plug on the passenger side--the alternator looks like its in the way. The 02 sensor looks easy to get to but i dont know how to change one and how to put the new wiring harness on.

I need to call somewhere else and see if they can pull a code even if the Check Engine Light isnt on. The last friggin thing i want to do is drop 200 bucks into a 700 dollar car, but i did get a good deal on it. Oh well.