inconsistent idle, please help!
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7th Gear
Joined: Jun 2024
Posts: 7
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inconsistent idle, please help!
need help weeding out an inconsistent idle and "popping" noise on my 92 302.
Current issue is that the idle cannot decid between 700 ish or 1100 or anywhere in between, and anything below 2200 the rpms fall much slower than is comfortable for shifting. 2500-5000 the rpms drop quickly and makes the shift timing perfect. I suspect that the idle and slow falling rpms are related. Additonally, there is a sort of intermittent "popping" noise at idle coming from what I assume is the engine, but can be heard via the tailpipe. Recently the check engine light came on and will stay on after about 5-10 minutes of driving, but goes away after killing the motor and firing it back up. Running the CEL self test gives me this pattern: 1,1 ,1 ,1 ,1, 3 ,3 ,3 ,3. From what i understand the initial 1 1 1 is a test pass for immediate codes, and the KAM codes I cannot find information for on 4 3's in a row. However 13, 333, 133 and combinations seem to be idle rpm and EGR related.
While trying to track this down I have
-replaced IAC with (this helped A LOT- i was running with no IAC and a cranked up set screw to make RPMs drop nicely when it was pissing me off)
-ensured TPS is within correct voltage range
-cleaned o2 sensor (worth replacing?)
-cleaned MAP (worth replacing?)
-cleaned throttle body
-currently attempting to clean the EGR but as I type this there is some torrential downpour going on outside.
I'd have to assume its something airflow related and im getting a bad mixture? It really has me stumped any help would be appreciated greatly.
Current issue is that the idle cannot decid between 700 ish or 1100 or anywhere in between, and anything below 2200 the rpms fall much slower than is comfortable for shifting. 2500-5000 the rpms drop quickly and makes the shift timing perfect. I suspect that the idle and slow falling rpms are related. Additonally, there is a sort of intermittent "popping" noise at idle coming from what I assume is the engine, but can be heard via the tailpipe. Recently the check engine light came on and will stay on after about 5-10 minutes of driving, but goes away after killing the motor and firing it back up. Running the CEL self test gives me this pattern: 1,1 ,1 ,1 ,1, 3 ,3 ,3 ,3. From what i understand the initial 1 1 1 is a test pass for immediate codes, and the KAM codes I cannot find information for on 4 3's in a row. However 13, 333, 133 and combinations seem to be idle rpm and EGR related.
While trying to track this down I have
-replaced IAC with (this helped A LOT- i was running with no IAC and a cranked up set screw to make RPMs drop nicely when it was pissing me off)
-ensured TPS is within correct voltage range
-cleaned o2 sensor (worth replacing?)
-cleaned MAP (worth replacing?)
-cleaned throttle body
-currently attempting to clean the EGR but as I type this there is some torrential downpour going on outside.
I'd have to assume its something airflow related and im getting a bad mixture? It really has me stumped any help would be appreciated greatly.
Thread Starter
|
7th Gear
Joined: Jun 2024
Posts: 7
Likes: 0
Oxygen sensor was hand tight, soaked in cleaner for 30 minutes and reinstalled. Looked old but i figure it would be running worse if it was totally shot.
MAP sprayed with electric parts cleaner, shot out one or two black specks, didnt seem to make a difference.
By canister do you mean the smog system cans?
MAP sprayed with electric parts cleaner, shot out one or two black specks, didnt seem to make a difference.
By canister do you mean the smog system cans?
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