I am getting an intermittent 'check engine' light on my 85 GT. (4sp / 2.8 )

Light will come on briefly, then go out..

Local driving.. about 5 sec
Highway driving.. about 2 min

EGR valve tests ok, engine runs great, just wont hold a code long enough for scan..

ANY ideas GREATLY WELCOME!!

thanks!

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88 coupe
85 GT
84 SE

Poor electrical connection somewhere. Sorry to be so vague, but with the info you have provided, that's the best I can do at thia time.

If the check engine light comes on, an error code should be stored and can be retrieved. It may not be on long enough for a scan, but it still should be in the computers memory. Do a search on how to retrieve the stored codes. If there are no error codes, then as 30 + said there may be a loose connection.

Or a bad ecm.....I hope not!

Phil

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GTDude
OVER 25 years GM experience

To test for codes is easy. Just take the black plate off over the cig light (2 torx screws) Then get a light and look at it, there are only two of the holes in the black connector that have metal pins right next to each other, they are on a horizontal plane. Stick a paper clip in there to short out the connection. Now turn the key to the run position, do not start the car. Now the check engine light will flash. It will flash the codes three times. The codes are 2 digits. the first set flash slow, then pause then quick. so Flash pause Flash Flash would be twelve: Flash Flash pause Flash Flash Flash would be 23. It will flash 12 three times first to say that everything is ok.

Probably the O2 sensor

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Thanks for the input! I'll check it out and post an update!

Icebear

How long since you replaced the pickup coil?
Thats what I needed for the same symptoms.