Rough idle, wont pass emissions help please.
03-15-2009, 12:58 AM
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Rough idle, wont pass emissions help please. Hey guys, My car was misfiring pretty bad at around 2k-3k rpm So I replaced my opti. Now my car is running very rough at idle it jumps between 700-1200rpms at idle. It is missing through out all rpms. The car is also pinging very bad when I give it a quick rev the scanner is showing the pcm is pulling 10-17 degrees of timing and under acceleration the scanner is showing the pcm is pulling 12 degrees of timming at idle the scanner shows the timing from 18-24 degrees im not sure what that means. My Dad has a 95Z28 that is running flawlessly so I have switched a few parts to eliminate them as part of the problem. so far I have switched the MAF, MAP, and the PCM, none of those made a difference. I currently have a snap-on scanner tool that I am borrowing from the nissan dealership my bro works at. It is showing my o2 sensors are good the mv jump up and down when I rev it showing there good.
the tps is reading .64v at idle wich is in tolerance of .3v-.9v @ idle. Im not sure what the iac is suppose to be reading but the scanner shows it is working I cant remember off the top of my head what the numbers were.
I have checked that my plug wires are going to the right plugs and are on the right connections on the opti. i have also just replaced the fuel filter today and that made no difference either. we also checked the headers with an infared thermometer and all cylinders are around the same degrees none are cold.
The car was not pining before I changed the opti. I have 94octane fuel in the car right now.
Car and mods in sig.
If anyone has any advice or what I can look for on the scanner I would really apreciate it, as I am completley lost on what to do or check now.
the tps is reading .64v at idle wich is in tolerance of .3v-.9v @ idle. Im not sure what the iac is suppose to be reading but the scanner shows it is working I cant remember off the top of my head what the numbers were.
I have checked that my plug wires are going to the right plugs and are on the right connections on the opti. i have also just replaced the fuel filter today and that made no difference either. we also checked the headers with an infared thermometer and all cylinders are around the same degrees none are cold.
The car was not pining before I changed the opti. I have 94octane fuel in the car right now.
Car and mods in sig.
If anyone has any advice or what I can look for on the scanner I would really apreciate it, as I am completley lost on what to do or check now.
Last edited by airfix; 03-15-2009 at 01:18 AM.
03-15-2009, 01:22 PM
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i had this problem but it was my TPS it was .80V at idle but the % was not at 0% is your TPS at 0% at idle with your foot off the throttle? when mine was going bad it reved from idle to about 1500 RPMS i replaced it and it fixed it i also found one of the plug wires was not on all the way one time and it did this. What scanning program are you using?
