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many new parts still a rough idle and service light


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codes current p1404 pcm, u1255 ipc, b1341 acm, history p0300 pcm, b1771 irc, u1255 irc, b2560 rfa; i am just trying to get my service light off without pulling the light bulb out. ha. i have replaced everything waterpump and all gaskets thermastat, radiator, spark plugs, egr valve, fuel filler tube, cat convertor had the ignition mod. tested along with the coils. need help with were else to check for the rough idle and even after i replaced the cat convertor i have an egg smell.

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codes current p1404 pcm, u1255 ipc, b1341 acm, history p0300 pcm, b1771 irc, u1255 irc, b2560 rfa; i am just trying to get my service light off without pulling the light bulb out. ha. i have replaced everything waterpump and all gaskets thermastat, radiator, spark plugs, egr valve, fuel filler tube, cat convertor had the ignition mod. tested along with the coils. need help with were else to check for the rough idle and even after i replaced the cat convertor i have an egg smell.
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Have you looked those codes up? http://myweb.accessus.net/~090/dtcobd2.html

Have you cleaned the TB? I see you replaced the plugs, but what about the wires? Also check the FPR for a leak.

i did clean the tb plug wires are fine and checked the fpr no leak. still getting code p1404 everytime after i clear my codes

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P1404 - Exhaust Gas Recirculation (EGR) Closed Position Performance

Check to see if the gasket under the EGR is tight and not leaking, is the EGR a NEW EGR? You seem to be getting EGR flow when the EGR is suppose to be closed. Check the EGR tube for damage. I would gently lift the EGR and see if it is stuck OPEN

How did you determine the ignition wires were fine? Ohm meter? You are also getting a misfire code P0300

You replaced your CAT?

As was mentioned did you check your FPR?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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This is in response to your PM to me.

It sounds like your EGR SHOULD be CLOSED and its CLOSED performance is not what the PCM expects. To me that would mean that it might be stuck open. However, if it was STUCK open, you would get a P1406 pindle position code also... The P1404 is not showing in my FSManual. Was this an OEM GM EGR valve or an aftermarket unit? Check the connectors on the top of the EGR for a positive connection

I would gently remove it and take a look at what is going on with the pindle. AN OPEN EGR valve will screw up the idle.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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You are also getting a misfire P0300.

You have replaced the plugs? All gapped, have you checked for cracks

Test the ignition wires with an ohm meter, are they AC DELCO?

If you have had the injector rail off, is it seated down perfectly and did you replace the injector o-rings?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Did you have this EGR P1404 code before you changed the EGR valve?

Is this an aftermarket EGR valve?

See this link on the P1404, it is saying what I was saying that the EGR must be stuck open, the idle you have kind of indicates that it might be open. Was it NEW?

http://gearchatter.com/viewtopic8967.php

With regard to the Misfire code P0300

If you have checked the plugs, wires, coils, ICM, you will need to do a compression test and check the injectors.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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i had a 0420 and o2 bad after the cat. i replaced both with aftermarket from advanced. same with the egr. as for the 1404 it has been there for awhile. it is "egr closed position performance(p1404)" i am going to pull off and check the egr and connector plus the wires tommorow i just need the ohms for the two i have been looking i havent found them yet.. i just bought the multimeter today. wish me luck..

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i had a 0420 and o2 bad after the cat. i replaced both with aftermarket from advanced. same with the egr. as for the 1404 it has been there for awhile. it is "egr closed position performance(p1404)" i am going to pull off and check the egr and connector plus the wires tommorow i just need the ohms for the two i have been looking i havent found them yet.. i just bought the multimeter today. wish me luck..

Are you saying that you had the P1404 BEFORE you replaced the EGR valve?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Update: bought some top engine cleaner and ran it through the pcv port, bought new wires and more plugs this time autolites double platium, also vacuumed out the plug ports then cleaned them with elec cleaner. I ran the car down the road and came back. new code p0405 will they ever end anyways "position sensor circuit low voltage" why is it throwing this code? i am going to double check my egr gasket tommorrow as i do not have a deep well 10mm.

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Finally fixed!! no light!! I found that the egr that i put on was backwards.. Also, I figured out that my spark plug electrods were bending as they where dropping into the sparkplug well. I used a magnet to install them this time.. Thanks for everyones replys I found were my problem areas were. Thanks again bodybyfisher and ranger your life saviors!!

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Hey I am glad you got it fixed, thats great. Keep an eye on this car, if it begins to misfire GET RID of the Autolites, AC DELCO are the ONLY plugs you should use... because:

1) they were tested and validated for YOUR engine, YOU are doing the validation on the Autolites, as a point of reference, I had an 86 vette, and it idled badly on Bosch plugs,

2) GM engines are sensitive to aftermarket plugs, poor idle, mis fire, poor longevity,

3) the spark plug threads are treated with a compound to prevent the plugs from seizing in the head, important, you don't want to wipe out the spark plug hole thread in the head

Glad WE could help, Mike

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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