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Jerk feeling


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When my car is not moving like if its in park or in drive but with the brake pedal pressed... i feel the engine jump or jerk a lil.. its not a real hard jerk but its noticeable... when i look under the hood with the car in park i can see the engine jerking a lil every few seconds... any ideas as to what this could be?

:huh:

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dog bones and/or motor mounts ???

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Possibly an intermittent misfire on one plug.

i just had the plugs changed... and i still fell it... i added some lucas heavy duty engine treament and it helped alil...maybe i should have added the whole thing

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can you explain it alittle better... is it a jerk or a miss...

big differents IMHO ...

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What is your IDLE RPM? I tend to think engine mount also, lift the hood, put it in D and R, keep foot on brake and GENTLY give it gas against the brakes and watch the engine to see if you get excessive movement. It is better if you look while someone else does this also, as you can look closely WHILE YOU STAY CLEAR OF THE CAR AND ENGINE...

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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What is your IDLE RPM? I tend to think engine mount also, lift the hood, put it in D and R, keep foot on brake and GENTLY give it gas against the brakes and watch the engine to see if you get excessive movement. It is better if you look while someone else does this also, as you can look closely WHILE YOU STAY CLEAR OF THE CAR AND ENGINE...

the problem is that sometimes it doesnt do it at all... i think something in the computer is messing with the tranny...

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when i look under the hood with the car in park i can see the engine jerking a lil every few seconds... any ideas as to what this could be?

Was this done with the engine just idling? ie no one in the car?

Jonah

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when i look under the hood with the car in park i can see the engine jerking a lil every few seconds... any ideas as to what this could be?

Was this done with the engine just idling? ie no one in the car?

i did it with the engine idling.. in "P". and thats when i got the two codes C1227 current.. and c1246 current.

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when i look under the hood with the car in park i can see the engine jerking a lil every few seconds... any ideas as to what this could be?

Was this done with the engine just idling? ie no one in the car?

i did it with the engine idling.. in "P". and thats when i got the two codes C1227 current.. and c1246 current.

So would it be accurate to say that it does not idle smoothly?

Jonah

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when i look under the hood with the car in park i can see the engine jerking a lil every few seconds... any ideas as to what this could be?

Was this done with the engine just idling? ie no one in the car?

i did it with the engine idling.. in "P". and thats when i got the two codes C1227 current.. and c1246 current.

So would it be accurate to say that it does not idle smoothly?

you can say that.. i do feel a slight jerk or jumping feeling from the engine when im not in motion..

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C1227 - Left Rear Excessive Wheel Speed Variation

C1246 - Brake Lining Wear Circuit Open

The C1227 might indicate that you have a bad hub bearing, there is a speed sensor that is part of the hub bearing, and the C1227 is related to the brake wear sensors not being connected when the brakes were worked on.

I do not believe that either of these codes are related to the jerk you are feeling

Its very hard to diagnose your problem here, I am not sure if you are talking about a mis or a mechanical problem, the jumping feeling to me sounds like a mis

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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C1227 - Left Rear Excessive Wheel Speed Variation

C1246 - Brake Lining Wear Circuit Open

The C1227 might indicate that you have a bad hub bearing, there is a speed sensor that is part of the hub bearing, and the C1227 is related to the brake wear sensors not being connected when the brakes were worked on.

I do not believe that either of these codes are related to the jerk you are feeling

Its very hard to diagnose your problem here, I am not sure if you are talking about a mis or a mechanical problem, the jumping feeling to me sounds like a mis

if its a miss... what could be the problem... it was doing it before i got the plugs change and its doing it afterwards... i read a thread on here stating that the crank sensor should be changed on my model.. could that help?

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Crank sensors should not cause a mis, they cause a sudden stall.

This is tough to diagnose here, but try this, idle the car, put it in drive and look at the RPM, is it varying much or staying steady?

Have you ever seen the Check Engine Light flash?

Have you seen a PO30x where x is 1 through 8?

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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Crank sensors should not cause a mis, they cause a sudden stall.

This is tough to diagnose here, but try this, idle the car, put it in drive and look at the RPM, is it varying much or staying steady?

Have you ever seen the Check Engine Light flash?

Have you seen a PO30x where x is 1 through 8?

once i get off work i will try the idle method.. but the engine light was on before, and when i check the codes thats when i recieved all thos old history codes, and then it went away. this morning the car drove fine.. my trans fluid smells burnt.. i will take it tomorrow to get the trans fluid changed.

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my trans fluid smells burnt.. i will take it tomorrow to get the trans fluid changed.

When you take it to get it changed, I dont think you want to let them flush the system. I think you just want it to be drained and refilled. Am I correct?

Jonah

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my trans fluid smells burnt.. i will take it tomorrow to get the trans fluid changed.

When you take it to get it changed, I dont think you want to let them flush the system. I think you just want it to be drained and refilled. Am I correct?

THATS CORECT! sorry bout the caps... but yea i read in another post that tran flush is the worst thing to get... so imma hve them drop the pan clean the screen and change the filter... which compay makes the deron 4 fluid?

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THATS CORECT! sorry bout the caps... but yea i read in another post that tran flush is the worst thing to get... so imma hve them drop the pan clean the screen and change the filter... which compay makes the deron 4 fluid?

The caps are ok there. Youve done your reading... good job!

I assume you mean Dexron... should be GM fluid... accept no less.

I am off to ride to campus and scan that page for you as soon as the rain lets up.

Jonah

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Do not use Dexron 4 use Dexron 3, not need for it and it might make shifting rough. If the tranny pan seal is a OEM seal, it can be reused, DO NOT allow them to use a CORK gasket it will leak badly in short order

I use CAPS for emphasis

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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Do not use Dexron 4 use Dexron 3, not need for it and it might make shifting rough. If the tranny pan seal is a OEM seal, it can be reused, DO NOT allow them to use a CORK gasket it will leak badly in short order

I use CAPS for emphasis

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i dont know if its an OEM seal or not. and where can i get the best dexron 3 fluid from?

o and thanks once again for everyone's help!!

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forgot one other thing.. since iam buying my fluid... how much will i need? im sure it states in the mannual.. juist figured i'll ask you guys... :huh: thanks

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forgot one other thing.. since iam buying my fluid... how much will i need? im sure it states in the mannual.. juist figured i'll ask you guys... :huh: thanks

wal-mart or any parts store should have dexron ...

also you tranny shop should have it ...

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What is your IDLE RPM? I tend to think engine mount also, lift the hood, put it in D and R, keep foot on brake and GENTLY give it gas against the brakes and watch the engine to see if you get excessive movement. It is better if you look while someone else does this also, as you can look closely WHILE YOU STAY CLEAR OF THE CAR AND ENGINE...

The idle rpm gauge was a lil more over one while the car was in park... and in drive with foot on brake it was between the 1/2 mark and 1...

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What is your IDLE RPM? I tend to think engine mount also, lift the hood, put it in D and R, keep foot on brake and GENTLY give it gas against the brakes and watch the engine to see if you get excessive movement. It is better if you look while someone else does this also, as you can look closely WHILE YOU STAY CLEAR OF THE CAR AND ENGINE...

The idle rpm gauge was a lil more over one while the car was in park... and in drive with foot on brake it was between the 1/2 mark and 1...

Its idling at 1,000 in park and 750 RPM in drive? That is too fast I believe. I am idling at 650 in DRIVE.. THAT in combination with a bad mount could be causing your jerking, you need to have someone take a look at the car familiar with its normal behavior...

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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What is your IDLE RPM? I tend to think engine mount also, lift the hood, put it in D and R, keep foot on brake and GENTLY give it gas against the brakes and watch the engine to see if you get excessive movement. It is better if you look while someone else does this also, as you can look closely WHILE YOU STAY CLEAR OF THE CAR AND ENGINE...

The idle rpm gauge was a lil more over one while the car was in park... and in drive with foot on brake it was between the 1/2 mark and 1...

Its idling at 1,000 in park and 750 RPM in drive? That is too fast I believe. I am idling at 650 in DRIVE.. THAT in combination with a bad mount could be causing your jerking, you need to have someone take a look at the car familiar with its normal behavior...

ok ive now noticed that wen the car is cool the hard shifting is not there... but after it warm up n drives for a lil it shifts hard and my power steering gets a lil stiff. After it sits for about and hour or a lil less it then drives fine and then warms up and start shifting hard. The trans fluid smells burt .. iam going to get the fluid changed tomorrow and see if that helps... any suggestions? also could a bad spark plug job cause a shifting problem?

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