Mis fire
06-23-2013, 03:24 PM
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Mis fire I have a 1994 formula, stock with bolt ons. Recently did an egr delete with pacesetter long tube headers. Did fine for awhile but now under a load...like accelerating getting onto interstate it'll misfire and stutter. Also seems to idle lower now around 500 to 700 in gear.
06-23-2013, 11:11 PM
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Please let me know when you find the problem! Mine is doing the same thing, and it wants to cut off when I come to a stop. I haven't looked at it too much because i bought it and put it in storage after 2 weeks because I left for the summer. I know it could be one of many things. I got that SLP CAI and the 2 small cone filters are dirty. Let me know if you figure it out and good luck!
06-26-2013, 07:52 PM
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when i installed the longtube headers i broke the coolant temp switch on the drivers side head...i wasnt worried about it because all it does is work the temp gauge...the more i look around online i see that theres another one on the water pump and that people have had mis fire problems exactly like mine when they go back. Anyone else had that problem?
06-26-2013, 11:20 PM
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I have been doing lots of research.. Try your oxygen sensors. That's the first thing i'm gonna try when I get back to my car. If you do them let me know. I work at advance Auto parts and the aftermarket 02 sensors are 60$. You can go on rockauto.com and get Delco's for under 35$
06-27-2013, 08:22 AM
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when my o2 sensor went bad i had horrible horrible misfire, it was constant and my little hand reader was showing some extreme values.... Considering you just did headers though im going to suggest looking at wires and o2 sensors. A lot of the time the wires come in contact with the headers and burn through, or the coating on the headers destroys the o2 sensors.
06-27-2013, 12:53 PM
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Yea I just replaced both o2s yesterday and bought the wire extensions offline but still messing up, seems to be more so when it's hot. Idle also drops pretty low and almost cuts out in gear
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06-27-2013, 01:06 PM
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just out of curiousity you can unplug the neg cable from the battery for about 30 minutes and it resets all computer readings... I'd go over all spark plug wires though for the rubber insulator could be heating up and causing a arc from the wires to the headers...
06-27-2013, 02:40 PM
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That sounds good.. My hesitation happens when I take off.. and it's a real bad, constant hesitation. It wants to stall out when I come to a stop without putting the car in park. Do you guys know of a way the keep those plug wires from getting too close to the headers? Something to use to insulate them? I re-routed mine already, they do not sit on top of the valve covers anymore.
06-27-2013, 06:55 PM
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I changed the coolant switch and coolant sensor today, drove it around about a hour before it started messing up...just stutters from about 1600 to 2000 rpm. I'm out of ideas now, may hook it to the scanner and see what I can find
06-28-2013, 09:46 AM
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Check to make sure your water pump isn't leaking on the opti.
Random problems after an hour could be opti, heat soak on ignition parts, Exhaust leak or plugs loose in head. Double check that all plugs are properly seated and tight in the heads and the insulators are not cracked. Also check to make sure the exhaust has no leaks that could cause false reading by the O2 sensors.
Random problems after an hour could be opti, heat soak on ignition parts, Exhaust leak or plugs loose in head. Double check that all plugs are properly seated and tight in the heads and the insulators are not cracked. Also check to make sure the exhaust has no leaks that could cause false reading by the O2 sensors.
06-28-2013, 02:01 PM
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could be opti, what opti is in it. I know i had a similiar problem turns out the rotor ws arcing on the cap but would clear up once i was above 3k rpms. I still wouldn't be prime suspect on opti though and id look at plugs and plug wires at night. See if they are arcing anywhere.
06-28-2013, 06:17 PM
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I ran it on the scanner today and the only codes were 27-EGR electrical fault, because of the egr delete. And 66- a/c pressure sensor/circuit problem, because if the a/c delete. Left o2 was at 890 mv right was at 841 mv
07-10-2013, 10:53 PM
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Did u have any welding done on the car? After a lot of welding for exh work my car was a little wacky - fans coming on and off, SES coming on and off - so i got my computer tuned and now the car is running much better with the computer reflashed (and tuned).
Hope this helps,
cardo
Hope this helps,
cardo
07-11-2013, 04:09 PM
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yes, i just had a full exhaust system welded on, im leading toward replacing the plugs and wires again but this will be the third set of otvc wires ive put on within the past 6 months to a year so im trying to really pin point the problem first