92 rough idle/warmup - MustangForums.com

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92 rough idle/warmup

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Old 11-27-2015, 08:39 AM
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Glocker23
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Default 92 rough idle/warmup

I have a problem where it is a rough idle on startup and takes a while to get warm and running good. On these start ups its running very rough where idle drops low then regains and so forth. So low you think it will stall and turn off. I bought it a couple months ago and it def has some mods including a F303 cam. I know it is a rough cam but right now I still cant imagine it would be that bad at idle. I am not sure if it has been chipped.

Once it is warmed up it is great, but it does take a while to get there.
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Old 11-27-2015, 08:42 AM
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Phillip123
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Does it have rough idle for 2-3 minutes after start-up and than runs fine? If that's the case it might be O2 sensor so check that first.
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Old 11-27-2015, 08:46 AM
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It runs rough for more sometimes will sit in driveway for 5-10 before we get anywhere. As far as O2 sensors....Prior owner took out all.....i mean everything for emissions. Luckily 2 more years and I too wont have to worry about it anymore either
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Old 11-29-2015, 11:12 AM
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Dencon
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I am sure you still have your O2 sensors. That is if you still have all the computer controls and the stock Fuel Injection system, of things would not work. I am in the process of removing all of my emissions crap, I am replacing my stock H pipe that has the Cats with one from LMR and it has the spots for the O2s.
I have been going through some idle problems and I pretty much got it figured out. It has turned out to be my ICA Valve. First try cleaning it. Here is a link that will help.
http://www.muscularmustangs.com/iac.php

You should also do a KOEO/KOER test. See if you have any codes and go from there. I stared with these and went from there.
http://sbftech.com/index.php/topic,2471.0.html
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Old 11-29-2015, 06:38 PM
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mongolchuck
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O2 sensors are not used to regulate fuel at start up. The engine is in "open loop" for a few minutes. When it goes into closed loop the O2 sensors take over fuel management.
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Old 11-30-2015, 09:17 AM
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88 orangepeel notch
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Pull codes the report back with what you find. That will help narrow it down.

And just for giggles, verify if you have O2 sensors.

Or did the PO convert to carb ?
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Old 12-01-2015, 08:44 PM
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Originally Posted by Dencon View Post
I am sure you still have your O2 sensors. That is if you still have all the computer controls and the stock Fuel Injection system, of things would not work. I am in the process of removing all of my emissions crap, I am replacing my stock H pipe that has the Cats with one from LMR and it has the spots for the O2s.
I have been going through some idle problems and I pretty much got it figured out. It has turned out to be my ICA Valve. First try cleaning it. Here is a link that will help.
http://www.muscularmustangs.com/iac.php

You should also do a KOEO/KOER test. See if you have any codes and go from there. I stared with these and went from there.
http://sbftech.com/index.php/topic,2471.0.html
I will look into this. Those tests confuse me. Will have to find more reading on it. Plus looks like I need a multimeter of some kind too.

And thanks for these links. Will def clean the ica valve soon. Car just went into garage til spring so best time to get these issues knocked down.
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Old 12-01-2015, 11:03 PM
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Dencon
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I felt just like you a few months ago when those very links were suggested to me. The I just read them step by step as I did the test, and it turned out to be easy. Now I just do the KOEO/KOER tests like second nature whenever I am tinkering on the car or change something.
Listen, I just bought this car last May. My toys before it were a 72 Chevelle wagon and a 79 Chevy C10. Both carb cars. Talk about a fish out of water gettign rid of those cars and now having, To me (With a small laugh) a late model computer car. So I was very, very confused. If I can figure it out, anyone can. You can get a pretty inexpensive multi meter at Harbor Freight. I got a real high dollar one I bought from the Mac tool guy when I was an auto tech back in the 90s. My roommate picked one up for $5.00 on sale at Harbor Freight and I use his most of the time. I might get one for myself. Its allot smaller then my Mac tools one.
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Old 12-02-2015, 12:03 AM
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Originally Posted by 88 orangepeel notch View Post
Pull codes the report back with what you find. That will help narrow it down.

And just for giggles, verify if you have O2 sensors.

Or did the PO convert to carb ?
Will do. It may be a little while. Still need to get a multimeter and got some house stuff I have been putting off lol
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Old 12-02-2015, 01:53 AM
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Originally Posted by Dencon View Post
I felt just like you a few months ago when those very links were suggested to me. The I just read them step by step as I did the test, and it turned out to be easy. Now I just do the KOEO/KOER tests like second nature whenever I am tinkering on the car or change something.
Listen, I just bought this car last May. My toys before it were a 72 Chevelle wagon and a 79 Chevy C10. Both carb cars. Talk about a fish out of water gettign rid of those cars and now having, To me (With a small laugh) a late model computer car. So I was very, very confused. If I can figure it out, anyone can. You can get a pretty inexpensive multi meter at Harbor Freight. I got a real high dollar one I bought from the Mac tool guy when I was an auto tech back in the 90s. My roommate picked one up for $5.00 on sale at Harbor Freight and I use his most of the time. I might get one for myself. Its allot smaller then my Mac tools one.
Just read through this 3 times. Will ask this. Anyone near or in Connecticut. Lol. Wow. It's confusing as hell. Will try again with the car in front of me instead of at work at 2am
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