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Discussion Starter · #1 ·
My brother's 1987 corvette has 110k on the speedo. I have replaced a lot of parts on it since he bought it last September. Today it has me stumped. It runs fine for about 20 minutes. Then he tells me the fuel mileage indicator will show fuel mileage drops to 13 to 18 mpg then the SES light comes on and sometimes the engine will surge at 40 mph if he either lifts or accelerates the surge will leave but the mileage is still low. It has three codes 32 EGR FAILURE 42 ELECTRONIC SPARK CONTROL and 44LEAN EXHAUST. The egr and 02 sensor are less than 9 months old. I removed the EGR and made a block off plate just to make sure the EGR was not letting exhaust gases into the engine. I also checked for vacuum leaks, checked and re calibrated his TPS witch is less than 9 months old and also checked his EST connector. But even after removing the EGR it still shows all three codes. The car drives normal except for the occasionally surging and poor fuel economy. I'm wondering if the ECM might be bad or something else that I missed. The problem seems to be heat related. Any thoughts?:lookinup:
 

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Discussion Starter · #2 ·
Well corvette lovers looks like it could be time to give gordon killebrew a call. I was hoping that someone might have a clue as what could cause all three codes to appear. If I had access to a factory service manual I would look up the condition that would be required to cause these codes to reappear over and over.:crazy:
 

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This one has me stumped as well. Maybe a plugged EGR pipe? I'm not sure what to suggest here, but this will bump your thread up if nothing else.
 

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Could be mass airflow sensor. Mine did weird stuff when it went south. Would be good if you have a known good one to swap.
 

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Discussion Starter · #5 ·
Yes I have the MAF off of my 1988 vette I will swap with him and see what happens. Thanks!:thumbsup:
 

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Discussion Starter · #6 ·
This one has me stumped as well. Maybe a plugged EGR pipe? I'm not sure what to suggest here, but this will bump your thread up if nothing else.
I am wondering what happens when the EGR has been removed and blocked off? I know some headers don't have a provision for an EGR tube so some people just remove the EGR valve and block it off and does this cause a code 32 EGR system failure?:crazy:
 

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I wouldn't rule out an ECM failure, either. The 1992 and '93 ECMs are especially prone to heat-related failures. They didn't get the heat sinks added until later and take quite a beating from engine heat wash.

Mine's a reman unit, but so far no problems.
 

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Discussion Starter · #8 ·
I wouldn't rule out an ECM failure, either. The 1992 and '93 ECMs are especially prone to heat-related failures. They didn't get the heat sinks added until later and take quite a beating from engine heat wash.

Mine's a reman unit, but so far no problems.
The ECM is the likely candidate but I would like to be sure before spending $100 plus dollars for the ECM and that's probably without the prom. But that's where most mechanics I know would end up after exhausting all other possibility's:thumbsup:
 

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Discussion Starter · #9 ·
Update.........We replaced the O2 sensor and all codes are gone so far! I think the bad O2 sensor was feeding a lot of bogus info to the ECM and causing the other codes to appear:crazy:
 
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