first problem...Vette cutting out

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Mar 30, 2009 | 09:58 AM

ELVIS' C4

Thread Starter

Instructor

Joined: Mar 2007

Posts: 129

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From: Sugar Land, TX (suburban Houston area) U.S.A.

St. Jude Donor '09, '13

first problem...Vette cutting out

Hi all:

Well after two years of weekend only cruising, something has popped up I am not sure where to start...thought I would post this & see if some can point out the obvious...

Saturday night, luckily near my house...under throttle it started "missing"...when I would coast smooth idle but as soon as I hit the throttle it would cut out intermittent...sometimes machine gun style! Coasted her home & back in garage but now not sure where to begin...no fault codes thrown, no recent work done to her, nothing.

Any ideas? Not sure if I could tie it back to anything but she was down to ~1/3 tank of gas & I have never run the car below 3/4 full in two years (she is very low mileage weekend driver...nothing too tough).

Any ideas where to start looking?

Thanks in advance for help!

JKK
92' Vette - LT-1/auto/~100K miles

Mar 30, 2009 | 10:38 AM

engle1147

Le Mans Master

Joined: Jul 2007

Posts: 5,043

Likes: 8

From: Tampa Florida

If no codes are present have a look at the air filter and/or the fuel system. Do some fuel pressure checks as well as some resistance check on the injectors.

Mar 30, 2009 | 10:40 AM

Elementaltoad

Instructor

Joined: Jan 2008

Posts: 118

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From: Austin Texas

http://forums.corvetteforum.com/c4-t...-when-hot.html

He has the same problem as us, it appears the be the opti, but it runs perfect while cold, 10-15 minutes after driving the problem starts.

Mar 30, 2009 | 11:02 AM

NEVRL8T

Race Director

Joined: Mar 2006

Posts: 11,628

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From: Sherwood, Arkansas

Sounds like the opti. Especially if no codes are being thrown.

Mar 30, 2009 | 12:25 PM

pcolt94

Le Mans Master

Joined: Jan 2006

Posts: 5,620

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From: Orlando FL

Sounds like a possible opti to me also. But first drive the car again when it is cold and see if the same symptoms are there. If it is good for 20 to 45 min, and then it acts up again, it would indicate a possible opti problem. If it is bad when cold, additional checking woud be in order, fuel pressure, ICM, etc.

Also check the hot coil wire near the top of the opti where it goes thru the water pump to see if it is arking in that area. Might be best to have it hot and while dark so it might show up better. Rev the engine would make it show up faster and easier.

Mar 30, 2009 | 12:33 PM

ELVIS' C4

Thread Starter

Instructor

Joined: Mar 2007

Posts: 129

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From: Sugar Land, TX (suburban Houston area) U.S.A.

St. Jude Donor '09, '13

Thanks all. Will do some trouble-shooting w/ these tips this week.

Appreciate it & will keep you posted as to outcome!

Mar 30, 2009 | 08:30 PM

jfb

Team Owner

Joined: Mar 2001

Posts: 54,124

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From: Cincinnati, Oh USA

It is a common failure of old spark control modules to quit working when hot and begin working when cooled off.

Mar 30, 2009 | 08:47 PM

jimg's'93

Drifting

Joined: Nov 2005

Posts: 1,324

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From: Charlotte NC

I had the same issue last year. Turned out the coil wire and 2 others were arching bad. Replaced my wires and she ran like new Vette. They seriously looked brand new which is why I never thought about it. Go figure.