Misfire...tried everything

ashah000

New Member
Mar 23, 2004
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I dont own a mustang, but its my friends so here it goes...

My friends mustang has been misfiring for the last two weeks or so.
We have replaced:
Spark plugs
Wires
Distributor cap
Rotor
Fuel filter
Air filter

It is a 1995 mustang GT

The car runs fine when it is cold, but when it warms up a little it starts to get worse and worse... to the point where it is misfiring 50 times a minute (and i'm serious).

His temperature gauge does not reach the normal position it just raises a bit from the cold and then stops there. This started when the misfires started... so I looked around on the internet and some places said it could be a sensor. Could it be the coolant temp. sensor causeing the gauge problem, and the misfire, (if i remember correcly the coolant sensor has a lot to do with a/f ratios) So could a messed up coolant sensor, cause the misfire.

BTW he does NOT have a check engine light.

Thank you very much.:)
 
The gauge coolant temp sensor and the engine coolant temp sensor (EGT) are different sensors. The EGT is in the intake manifold runner of cylinder #5. Take the car to Autozone or some other auto parts chain store and have them pull the codes.
 
Well the light has never came on, since the car started misfiring. So there will be no codes that have to do with the misfire issue.

Also doesn't the car have to be 96+ for autozone to check it, his car is a 95. I think all autozone reads is OBDII
 
ashah000 said:
Well the light has never came on, since the car started misfiring. So there will be no codes that have to do with the misfire issue.

Also doesn't the car have to be 96+ for autozone to check it, his car is a 95. I think all autozone reads is OBDII

even if there aren't any codes related to this, you would want to fix those problems prior to attacking this as it will possibly make it harder to diagnose.

autozone should be able to pull the codes from ANY mustang. if not the tech section can explain how to do it with a paperclip.

-steve
 
ashah000 said:
Ok... Thanks. I will tell him to do that. Because last time I went there they said they car had to be 96+

i can't see why. oh well, like i said you can pull them yourself with a paperclip or small jumper wire. the instructions are in the tech section. you can get the codes (meaning) here or in a hayne's manual. just pm me if you run into any problems and i'll try to help.

-steve
 
ashah000 said:
I dont own a mustang, but its my friends so here it goes...

My friends mustang has been misfiring for the last two weeks or so.
We have replaced:
Spark plugs
Wires
Distributor cap
Rotor
Fuel filter
Air filter

It is a 1995 mustang GT

The car runs fine when it is cold, but when it warms up a little it starts to get worse and worse... to the point where it is misfiring 50 times a minute (and i'm serious).

His temperature gauge does not reach the normal position it just raises a bit from the cold and then stops there. This started when the misfires started... so I looked around on the internet and some places said it could be a sensor. Could it be the coolant temp. sensor causeing the gauge problem, and the misfire, (if i remember correcly the coolant sensor has a lot to do with a/f ratios) So could a messed up coolant sensor, cause the misfire.

BTW he does NOT have a check engine light.

Thank you very much.:)

Was this problem there before the tune up or was the tune up to try and fix. this problem? :shrug: If it was there after the tune up, you could have a cracked plug or defective plug wire. Generally the hotter the engine components become, the more resistance there is in the electrical components. I have seen this many times in ignition systems. And remember, just because the part is new, doesn't mean it can't be defective. Did he use good quality parts or cheapo brand? Is there alot of black smoke coming out of the tail pipe when this problem starts to happen? This would indicate a rich condition and could be caused by various different things. The engine temp could also cause this. If the ECT reads a certain voltage, say reading a voltage telling the ECM the car is still cold,the ECM will call for more fuel creating the rich condition. In short, the ECM thinks the engine is cold due to a faulty reading from the ECT sensor. Also an engine miss will act differently than a car running overly rich. Hope this helps and good luck.
 
It was there before, that is why we started to change everything. We used good parts. I will try to find out if he is running rich tomorrow. I'm confused... so could it be the coolant temp. sensor.

Also where can I find a link on how to read codes with a paperclip. I am looking for it on the site -- but i cant find it.
 
I haven't tried this with a 94-95, so I don't know if the test connector location is the same.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes. Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
 
If he has no codes try to reset the computer.Unplug the negative terminal for 5 minutes are so.Then plug it in and go for a highway drive for a couple miles keeping a steady throttle around 55mph.Don't get on it at all til you go for the little drive.When you reset the computer it will relearn everything again when you plug it back again.So try its free.
 
If he has no codes try to reset the computer.Unplug the negative terminal for 5 minutes are so.Then plug it in and go for a highway drive for a couple miles keeping a steady throttle around 55mph.Don't get on it at all til you go for the little drive.When you reset the computer it will relearn everything again when you plug it back again.So try its free.
 
We already tried to reset it, It did nothing. But we did not go on the highway and keep it at a steady throttle.

Also... he said that he got link error about 5 times before the guy said there are no codes. So I think I am going to take it to a different autozone. Stupid autozones.
 
We replaced the Coolant temp. sensor today... did nothing.
Went to another autozone... got "link error" everytime.

Does anyone have any other ideas that could be causing this?

I thought the coolant sensor would at least help the temp. gauge reach the normal position. But it is not. There is no change.

Please help us.