95 suddenly running very rough with some pinging
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From: Sacramento CA
95 suddenly running very rough with some pinging
My 95 typically runs great. Today, I started it up and it started running rough. Not just a rough idle, but running rough while driving, as well. It does smooth out some while driving, but I can still tell that it's rough compared to its usual very smooth running. It is also pinging a bit under load. This is all not typical at all. It never pings and typically runs so smoothly. It does still start up right away without any issue.
The other thing, and I don't know if they're related, is that the other day, it seemed to get "stuck" at a somewhat higher idle, around 1100. Turned off the engine and restarted, and it idled normal again. Apparently, this also happened once before, a few days earlier, when my husband was driving it.
No engine light on. I think that would mean no codes, but I could be wrong.
Checked TPS voltage from idle position to WOT, and was in specs, rose normally as expected from .58 up to 4.01.
Any ideas/suggestions would be appreciated. Thanks.
I should add that a visual showed nothing loose or no broken looking lines. Also, the car is stock.
The other thing, and I don't know if they're related, is that the other day, it seemed to get "stuck" at a somewhat higher idle, around 1100. Turned off the engine and restarted, and it idled normal again. Apparently, this also happened once before, a few days earlier, when my husband was driving it.
No engine light on. I think that would mean no codes, but I could be wrong.
Checked TPS voltage from idle position to WOT, and was in specs, rose normally as expected from .58 up to 4.01.
Any ideas/suggestions would be appreciated. Thanks.
I should add that a visual showed nothing loose or no broken looking lines. Also, the car is stock.
Last edited by laurieb; Jul 8, 2013 at 10:11 PM.
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From: Sacramento CA
Racer
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From: Austin Texas
Isn't it possible that this is evidence of an Optispark problem?
I say that ebcause the Optisaprk afefcts not only ignition, but also injectors, and you appear to be having symptoms related to both.
Since you have a 1995 model, have you recetly checked your Optisaprk vacuum lines for integrity?
Jim G
I say that ebcause the Optisaprk afefcts not only ignition, but also injectors, and you appear to be having symptoms related to both.
Since you have a 1995 model, have you recetly checked your Optisaprk vacuum lines for integrity?
Jim G
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From: Sacramento CA
I think the Optispark might be the original. The car just turned over 98,000. There is no random missing going on.
My husband is checking right now for any issues with the vacuum lines, shorting of plug wires and also is going to look at cats.
I appreciate all the help! Thanks so much to everyone and I'll report back what he finds.
My husband is checking right now for any issues with the vacuum lines, shorting of plug wires and also is going to look at cats.
I appreciate all the help! Thanks so much to everyone and I'll report back what he finds.
Racer
Joined: May 2008
Posts: 430
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From: Austin Texas
I keep reading here and elsewhere that it is really common for an Optispark wire (coil to Opti, etc) to "look" ok but to need reseating in its connectors. It appears that maybe either vibration or simple corrosion over time impairs the connections. Same thing happened on at least a couple of wiper control connections (including on my own C4). You might check all the wires.
Jim G
Jim G
Last edited by JimGnitecki; Jul 9, 2013 at 02:58 PM.
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Okay, so no sparking/arcing apparent when running in the dark. As far as getting a good look at Optispark and connection, I guess you have to look from the underside of the car? If so, that may be something for later, as my husband is still recovering from hip surgery, so getting under the car isn't a good idea for him.
We're wondering, though, could it still be optispark even though it's not missing? It also starts right up very easily. But it sure runs so rough and has some pinging under load. It's normally very responsive, too, and of course isn't right now.
We're wondering, though, could it still be optispark even though it's not missing? It also starts right up very easily. But it sure runs so rough and has some pinging under load. It's normally very responsive, too, and of course isn't right now.
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Checked the injector fuses. Neither is blown. Checked other fuses while in there, and none are blown. Was definitely hoping for that one, though. Would've been a very easy fix.
Optispark and stuck injector are currently at the top of the list of likely possibilities. It smells rich, like too much fuel in the mix. No smoke from exhaust.
Optispark and stuck injector are currently at the top of the list of likely possibilities. It smells rich, like too much fuel in the mix. No smoke from exhaust.
Last edited by laurieb; Jul 9, 2013 at 08:20 PM.
Racer
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From: Austin Texas
Checked the injector fuses. Neither is blown. Checked other fuses while in there, and none are blown. Was definitely hoping for that one, though. Would've been a very easy fix.
Optispark and stuck injector are currently at the top of the list of likely possibilities. It smells rich, like too much fuel in the mix. No smoke from exhaust.
Optispark and stuck injector are currently at the top of the list of likely possibilities. It smells rich, like too much fuel in the mix. No smoke from exhaust.
Jim G
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Yeah...we can't really test the Optispark, so will have to have our mechanic check that if injectors aren't the issue. As far as injectors, they look like they shouldn't be too hard on the LT1. Unfortunately, we only have a FSM for our 85, but don't yet have one for the 95. Will have to get one, but in the meantime, I've found some good write ups on changing the injectors and fuel filter.
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About a week ago. It made several trips without issue on that tank. Unfortunately, the issue came on suddenly two afternoons ago after having driven great that very morning.
