service engine soon =warning

[jamesmetairie]

"service engine soon" warning light comes on occasionally while i,m driving. after about 10 minutes it goes off. 1995 v/6 with 88,000 miles. anyone have or had this happen?

[GTP Dad]

The SES light indicates a malfunction in the emissions system or a misfire condition. I expect you probably have an O2 sensor going bad due to the fact that it goes away after you drive for a while. I suggest you try to get the code from the computer when the light is on so it will point you in the right direction.

[jamesmetairie]

Originally Posted by GTP Dad

The SES light indicates a malfunction in the emissions system or a misfire condition. I expect you probably have an O2 sensor going bad due to the fact that it goes away after you drive for a while. I suggest you try to get the code from the computer when the light is on so it will point you in the right direction.

how many 02 sensors does this car have? is misfire usually caused by faulty ignition wires or a fouled or a bad spark plug? if it is the o2 sensor,does it get progessively worse? will it affect performance and mpg,s? thanks.

[GTP Dad]

Your car probably has two but I am not certain. One on the downpipe behind the engine and one behind the cat. Cars vary and it is hard to say if they have one or two. Easy to find by simply looking. If the sensor is going bad it will get worse and the worse it gets the worse your fuel mileage will get. Performance usually will not suffer by you will feel it in the wallet.

Misfires can be caused by several things, plugs and wires are the most common cause. Bad coils, bad injectors, bad ignition module can all cause misfires. I always recommend that you start with plugs and wires and then try coils and finally the injectors. The ignition module is usually the last resort. Hope this helps!

[jamesmetairie]

Originally Posted by GTP Dad

Your car probably has two but I am not certain. One on the downpipe behind the engine and one behind the cat. Cars vary and it is hard to say if they have one or two. Easy to find by simply looking. If the sensor is going bad it will get worse and the worse it gets the worse your fuel mileage will get. Performance usually will not suffer by you will feel it in the wallet.

Misfires can be caused by several things, plugs and wires are the most common cause. Bad coils, bad injectors, bad ignition module can all cause misfires. I always recommend that you start with plugs and wires and then try coils and finally the injectors. The ignition module is usually the last resort. Hope this helps!

thanks for the reply. i don,t know if there,s a connection,but i got the oil changed at walmart two thousand miles ago. it took me 1/2 an hour to get them to agree to just put 3 or 4 quarts in.(it takes 4.5 with a new filter) i like to top it off myself. they finally said ok. i checked the dip stick immmediately after the oil change and as expected it was way over the full mark. yesterday i changed the oil myself. since then i have not noticed the service engine soon light. my fingers are crossed.

[jamesmetairie]

Originally Posted by jamesmetairie

thanks for the reply. i don,t know if there,s a connection,but i got the oil changed at walmart two thousand miles ago. it took me 1/2 an hour to get them to agree to just put 3 or 4 quarts in.(it takes 4.5 with a new filter) i like to top it off myself. they finally said ok. i checked the dip stick immmediately after the oil change and as expected it was way over the full mark. yesterday i changed the oil myself. since then i have not noticed the service engine soon light. my fingers are crossed.

it,s still coming on occasionally. usually on the interstate. and it goes off after awhile. i,m getting 31 mpg at 70 mph without the a/c nowadays. so it sure ain,t affecting mpg,s yet.

[GTP Dad]

Try to get it read when the light is on. You may have a misfire condition that is causing this problem. Fuel mileage is good so it probably isn't the O2 sensors but it could be a dirty egr or a bad wire or plug causing the problem. Other causes could be a loose or defective fuel cap. If you can catch it with the light on then you can get a definitive answer.

[jamesmetairie]

Originally Posted by GTP Dad

Try to get it read when the light is on. You may have a misfire condition that is causing this problem. Fuel mileage is good so it probably isn't the O2 sensors but it could be a dirty egr or a bad wire or plug causing the problem. Other causes could be a loose or defective fuel cap. If you can catch it with the light on then you can get a definitive answer.

nowadays it usually appears while i,m climbing an overpass on the interstate. then it stays on for about 15 miles. i tried auto zone,but they only check thru 1994 cars.

[GTP Dad]

Sounds like a misfire! Does the light flash when it comes on and then stays on steady or does it come on and stay on? If it flashes it is a misfire, if it comes on steady it could be a bad sensor, such as a knock sensor that is causing the issue. Try to get it scanned when the light is on. That is the only sure way to tell what is going on.

[jamesmetairie]

Originally Posted by GTP Dad

Sounds like a misfire! Does the light flash when it comes on and then stays on steady or does it come on and stay on? If it flashes it is a misfire, if it comes on steady it could be a bad sensor, such as a knock sensor that is causing the issue. Try to get it scanned when the light is on. That is the only sure way to tell what is going on.

not sure if it flashes first. this is a great car. but the a/c is shot and heater core is shot. i don,t want to invest in that stuff if it,s gonna have a sensor problem soon. i could keep it as is and just drive it,but here in katrinaland it,s like scorching nowadays.gotta have a/c.