Engine shutters and shakes at idle, CEL is on

Craig Mack

Busted Buffing the Bishop

Founding Member

Mar 9, 2002

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Lake Mary, FL

Aug 21, 2004

#1

• Aug 21, 2004

• #1

Hey guys.

I have almost 61k on my '97 Cobra. About 500 miles ago I got a complete check up. I got the oil changed, new plugs, new filters, completely new spark plug wires ($$$) etc. The car was running in tip top shape. All of a sudden today, my check engine light came on. I didnt hear anything out of the ordinary...

My car has always shuddered at idle. Every few seconds the seats shudder, you can feel it pulsating from the engine. I never thought anything of it. But since my CEL came on today, I popped the hood with the engine running at idle. The engine would shake noticeably back and forth lopey like, then stop and be calm for a few seconds, then shudder back and forth again. Should I be worried about this?

I took my car to Autozone to have the code scanned but they didnt have the scanner with them. The car just had its major check up and everything is supposedly running awesome, except for this engine shudder and newfound CEL.

Any advice is greatly appriciated.

 

5.0's 4 ever

The #1 Stunna

Founding Member

Jan 22, 2000

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76

Orlando, FL

Aug 21, 2004

#2

• Aug 21, 2004

• #2

First off you need to get the code pulled and find out what it is. Second does the car have a miss under acceleration?

 

Craig Mack

Busted Buffing the Bishop

Founding Member

Mar 9, 2002

801

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Lake Mary, FL

Aug 21, 2004

#3

• Aug 21, 2004

• #3

5.0's 4 ever said:

First off you need to get the code pulled and find out what it is. Second does the car have a miss under acceleration?

Click to expand...

I Know, definately gotta get it pulled. I'm going out tommorow again to try and find some autozone type place that will help me. The ECU is under the drivers seat, right?

What do you mean "miss"? It accelerates normally, but I haven't really pushed it since the CEL came on. I had to drop it into 3rd while merging on the highway tonite to pass some broad in a minivan before the lane ended, and the car felt slower than usual. Other than that, I haven't noticed any unusual blunders during acceleration.

Sometimes, with the A/C on, the car will studder at mid/high 2k rpm when I casually accelerate in 2nd gear, but its always done that. WOT has always been generally smooth though.

 

B

black98snake

New Member

Jun 16, 2004

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0

Aug 21, 2004

#4

• Aug 21, 2004

• #4

Could be dirty IMRC's. Crankshaft position sensor could be bad if you are having a hard time starting the car. Dirty IAC or MAF sensor.

 

Craig Mack

Busted Buffing the Bishop

Founding Member

Mar 9, 2002

801

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0

Lake Mary, FL

Aug 22, 2004

#5

• Aug 22, 2004

• #5

black98snake said:

Could be dirty IMRC's. Crankshaft position sensor could be bad if you are having a hard time starting the car. Dirty IAC or MAF sensor.

Click to expand...

I'm not having trouble starting it, although it studders a few times before turning over, but I presume its normal. Also, can I see the IMRC's if I take off the intake? When I did, the entire throttle body was SQUEEKY clean.

Would dirty IMRC's trigger a CEL?

 

missouri_guy197

New Member

Aug 31, 2002

1,441

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St. Louis, MO

Aug 22, 2004

#6

• Aug 22, 2004

• #6

Yep the IMRCs could trigger a CEL, but it wouldn't cause the car to have a miss like that...sounds like you have a problem with a spark plug or wire...

Go to another Autozone and have the code scanned before you go and try diagnosing anything more...

 

Craig Mack

Busted Buffing the Bishop

Founding Member

Mar 9, 2002

801

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Lake Mary, FL

Aug 22, 2004

#7

• Aug 22, 2004

• #7

Alright...i'll get it scanned and let you guys know what it shows up as.

 

Craig Mack

Busted Buffing the Bishop

Founding Member

Mar 9, 2002

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Lake Mary, FL

Aug 22, 2004

#8

• Aug 22, 2004

• #8

Well, something wierd happened. On the way to work while sitting at a stop light, as the light turned green and I accelerated, the CEL all of a sudden went off. ~4 hours later coming back it is still off.

Weird. I hope to God this isn't related to my MIL eliminators again. That was such a PITA. We'll see though.

 

Tat98Cobra

Founding Member

Nov 2, 2002

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Aug 22, 2004

#9

• Aug 22, 2004

• #9

With the cel on, you'll be in limp mode so it will be sluggish no matter what. If you cant get it scanned, try resetting the battery, then drive it again. See how it drives before the CEL comes back on. Sometimes, bad gas can trigger a CEL (usually show a lean condition from one or both front 02's) and clear itself after a new tank. Definately get it scanned though - sounds 02 related to me.

peace

 

N

Nicks98Cobra

New Member

May 30, 2004

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0

Aug 22, 2004

#10

• Aug 22, 2004

• #10

mine does the exact same thing yours is doing. Mine is caused by the air pump being bad. It sounds like a miss at idle but its from fuel building up in the cats and them causing a mini explosion. How much are new air pumps anyway?

 

Craig Mack

Busted Buffing the Bishop

Founding Member

Mar 9, 2002

801

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Lake Mary, FL

Aug 22, 2004

#11

• Aug 22, 2004

• #11

Nicks98Cobra said:

mine does the exact same thing yours is doing. Mine is caused by the air pump being bad. It sounds like a miss at idle but its from fuel building up in the cats and them causing a mini explosion. How much are new air pumps anyway?

Click to expand...

But I don't have any cats.

 

N

Nicks98Cobra

New Member

May 30, 2004

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Aug 23, 2004

#12

• Aug 23, 2004

• #12

Hummmmm. Well I hope you figure this out before I go buy a new air pump so Im not wasting my money.

 

Craig Mack

Busted Buffing the Bishop

Founding Member

Mar 9, 2002

801

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0

Lake Mary, FL

Aug 23, 2004

#13

• Aug 23, 2004

• #13

Nicks98Cobra said:

Hummmmm. Well I hope you figure this out before I go buy a new air pump so Im not wasting my money.

Click to expand...

lol, well I dont know if I should scan it unless the CEL comes back on. Maybe I have a retarded computer or something.

 

CobraSusie

New Member

Aug 17, 2004

43

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0

NW Indiana

Aug 24, 2004

#14

• Aug 24, 2004

• #14

Craig Mack said:

Hey guys.

I have almost 61k on my '97 Cobra. About 500 miles ago I got a complete check up. I got the oil changed, new plugs, new filters, completely new spark plug wires ($$$) etc. The car was running in tip top shape. All of a sudden today, my check engine light came on. I didnt hear anything out of the ordinary...

My car has always shuddered at idle. Every few seconds the seats shudder, you can feel it pulsating from the engine. I never thought anything of it. But since my CEL came on today, I popped the hood with the engine running at idle. The engine would shake noticeably back and forth lopey like, then stop and be calm for a few seconds, then shudder back and forth again. Should I be worried about this?

I took my car to Autozone to have the code scanned but they didnt have the scanner with them. The car just had its major check up and everything is supposedly running awesome, except for this engine shudder and newfound CEL.

Any advice is greatly appriciated.

Click to expand...

possibly a coil pack?

 

doogz

Founding Member

Apr 11, 2002

760

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0

London, UK

Aug 25, 2004

#15

• Aug 25, 2004

• #15

Nicks98Cobra said:

Hummmmm. Well I hope you figure this out before I go buy a new air pump so Im not wasting my money.

Click to expand...

The air pump won't cause any drivability problems. It'll throw a code if it's unplugged, but you won't notice a difference without it on. I simply unplugged mine and left it hanging there. No harm, no foul.

For the bucking problem, the MAF may be dirty or my bets are on the IAC being dirty.

 

Craig Mack

Busted Buffing the Bishop

Founding Member

Mar 9, 2002

801

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0

Lake Mary, FL

Aug 25, 2004

#16

• Aug 25, 2004

• #16

Can't be the coil packs, they were replaced when the car got a tune up less than 1,000 miles ago.

So, even if I take off the intake and look at the Throttle body, which was extremely clean, the IMRCs could still be gunked up? A dirty MAF is another possible solution. Maybe the shop got their greasy hands on the screen and didn't clean it off or something.

Two things though: The code is still off and hasn't reappeared, and the car runs smooth at WOT. Is it possible that whatever the problem was, the car corrected it by itself?