95 Mystique engine diagnosis

FunkALunk · #1 11-25-2004, 05:40 PM

Hey all, just wanted to see if I could get a little help. I have a 95 Mystique, with 2.0. This thing runs badly at idle, running really choppy. When driving, it lightly pulses forward and back. Gas mileage has gone downhill to probably 12-14 mpg. It was getting 28.

It also has a problem with staying cool, only not all the time. Sometimes it stays right on normal temp, but at other completely random times, it gets very close to overheating and has done so a couple of times.

Spark plugs, wires, fuel filter, and air filter have been replaced within the last year. I have replaced the thermostat, coolant temp sensor, water pump, timing belt, and timing belt idler pulleys. I have also replaced the MAF sensor.

I don't know if the two problems are associated, but they may be through the computer. I hooked it up to a Snap-on scanner, and could not get it to read data. The scanner could make the car idle faster in a test, but it would give me an error saying it was having trouble communicating. I am told that it could be the computer, but I wanted to see if anyone had the same problem at all and what they did to fix it.

I really appreciate any info you guys can give me.
Thanks.

ggcatt · #2 01-13-2005, 11:36 AM

I have a '95 Contour, and this is the year that Ford used the older OBD I diagnostics with the newer computer systems. Hence, most scanners can read codes or communicate with this system. This may be the reason your scanner can't connect with your car computer.

beyondloadedSE · #3 01-13-2005, 12:18 PM

Quote:

Originally Posted by ggcatt

I have a '95 Contour, and this is the year that Ford used the older OBD I diagnostics with the newer computer systems. Hence, most scanners can read codes or communicate with this system. This may be the reason your scanner can't connect with your car computer.

thats correct. An OBD-2 scanner will not read codes on an OBD-1 vehicle. Things I would check are the IAC valve, EGR valve, 02 sensors, fuel filter, or maybe your main catalytic convertor is bad. My main cat has failed 3 times, but luckily has been replaced under warranty everytime. Is your check engine light on?

FunkALunk · #4 01-16-2005, 11:13 AM

I didn't know that info on the scanners. The check engine light is not on.

FunkALunk · #5 01-21-2005, 07:06 PM

Fixed the problem, just in case someone else ever runs into this. When the timing belt was replaced, the new belt was put on one tooth off on the cam that controls the exhaust valves. This was causing the valves to open early, and the car was reacting very funny. I took it apart, moved it one tooth, put it back together and runs great.

Fgreco · #6 02-17-2005, 03:30 PM

HI I have a mercury also It is a 97 can anyone tell me how to read the codes. I got codes and dont know a site or book to get to read them thanks.

I would have said it was the water pump because mine did that also but, was fixed the the new water pump. sorry about your problem.

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