Check engine light

[czar]

During the winter, my check engine light went on, and ther car started to run poorly. I drive it around town (mostly), so I'm in 1st, 2nd, and 3rd gear a lot, and don't (usually) tend to go over 45 mph or so. Anyway, I'd had some rough idling a month or so before that happened, so I changed the plugs, air filter, etc., and it seemed OK. Now, it idles poorly (the tach jumps between 500-700) and it almost sounds like it's not firing on all 4 cylinders, but then it will kick back up to 900 rpm's or so and idle smoothly for a short time; it repeats this cycle. Around town, the gas mileage has dropped, and as soon as I let off the gas, I get more engine braking than is usually the norm. On the highway, however, it runs great. I can cruise at 70-80mph and it gets great gas mileage and no other symptoms. I pulled the plugs out and there is a lot of soot on them. Any ideas? It's a 96 ti.

Thanks!

[motorwerk]

During the winter, my check engine light went on, and ther car started to run poorly. I drive it around town (mostly), so I'm in 1st, 2nd, and 3rd gear a lot, and don't (usually) tend to go over 45 mph or so. Anyway, I'd had some rough idling a month or so before that happened, so I changed the plugs, air filter, etc., and it seemed OK. Now, it idles poorly (the tach jumps between 500-700) and it almost sounds like it's not firing on all 4 cylinders, but then it will kick back up to 900 rpm's or so and idle smoothly for a short time; it repeats this cycle. Around town, the gas mileage has dropped, and as soon as I let off the gas, I get more engine braking than is usually the norm. On the highway, however, it runs great. I can cruise at 70-80mph and it gets great gas mileage and no other symptoms. I pulled the plugs out and there is a lot of soot on them. Any ideas? It's a 96 ti.

Thanks!
What about checking the O2 sensor? Many times when the car runs poorly (or too rich or too lean), the O2 sensor is not working properly. This would also be a cause of the check engine light going off. Obviously the car is throwing a code...there should be a way in determining which code it is?! Anybody on this board know? thanks...motorwerk

[Tyler]

My car idles at 750rpm,which is normal

[czar]

What about checking the O2 sensor? Many times when the car runs poorly (or too rich or too lean), the O2 sensor is not working properly. This would also be a cause of the check engine light going off. Obviously the car is throwing a code...there should be a way in determining which code it is?! Anybody on this board know? thanks...motorwerk

These are the codes I get from a Peake Research tool (and their conversion from hex to decimal):

6C = (6x16 = 96 + C(12)) = 108


16 = (1 x 16 = 16 + 6) = 22


94 = (9 x 16 = 144 + 4) = 148

As for the proper idle speed, yes, mine's probably off. Ithink it used to idle somewhere around there. What's happening is that it idles in an up and down cylce, and then stabilizes once the computer gives it some more gas -- at that point, it will hover around a 1000 before it starts to idle erratically again.

As for the O2 Sensor, is there both a front and rear? Which one would need to be replaced?

[ClubSport]

Sounds like your idle control valve, ICV. Search for that.

[czar]

Sounds like your idle control valve, ICV. Search for that.


Good idea. I'd read about the ICV before, but fogured since I was not having spikes in idle, it would not be the culprit; however, it couldn't hurt to clean it and see. I'm also wondering if it might be the fuel injectors. So many different things to check!!

[chepas]

You may want to check the ignition wires and ignition coil...

[czar]

You may want to check the ignition wires and ignition coil...


Good idea, so I bought a set of wires, and I'll try to get them changed as soon as the rain stops :(

Thanks for the suggestion.

[KdCass]

Soo what happend?