LT 1 problems (running rough)

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LT 1 problems (running rough)

TonyRawls TonyRawls
I watched Corvette Summer | Posts: 1 | Joined: 01/09
Posted: 01/18/09
11:04 AM

Sometimes the car runs fine with no engine light on. Then all of a sudden it starts missing and a black thick smoke follows. When the engine light comes on, everything is fine and runs like it should. I've had previous problems with O2 sensors and I'm wondering if my problam has returned. Please help, I'm loosing my mind in Springfield,Mo. !! Confused??  !!  

55Guy 55Guy
Administrator | Posts: 210 | Joined: 07/06
Posted: 01/20/09
07:57 AM

Sounds like your Mass Air Flow sensor is going bad. Another possibility is your ignition module is going bye-bye. A lot of black smoke can come form the timing not being correct.  

94TealC4 94TealC4
I watched Corvette Summer | Posts: 4 | Joined: 02/09
Posted: 02/08/09
08:42 PM

Have you checked for stored codes? What year?  

Air_John Air_John
I watched Corvette Summer | Posts: 2 | Joined: 02/10
Posted: 03/06/13
10:29 AM

I had a problem where the engine would suddenly start running very rough, surging, etc after running for about 15 minutes, sometimes 30. I was getting one error code saying rich exhaust and at the same time getting the code for lean exhaust, and a code saying there was low voltage to the fuel pump. Car already has a new fuel pump and is getting power to it. Removed the ECM and found a connector pin was partially dislodged, pin D-1, one of the 12 volt connections. Next I opened the ECM and re-soldered some of the points on the circuit board where the connector pins attached there. Then I soldered pigtails onto all of the Ground wires going to the connectors, pins A12, D1, D3, and ran a heavy wire to a good Ground on the engine block. Used a very small wire brush to clean oxidation off of all the pins on the connector of the ECM. Engine has been running fine now for a week or so. It was weird to be getting one error code saying rich exhaust and at the same time getting the code for lean exhaust, made no sense, computer was not operating properly there.  

pepsi1 pepsi1
Duntov Incarnate | Posts: 88 | Joined: 01/12
Posted: 03/06/13
12:59 PM

What year is the your Vette? Could be a few things acting up.

Just going by what you have written, try this. Disconnect the O2 sensor or sensors.That will put the ECM in Open Loop, if the problem goes away go for the O2 senseor/sensors first. Do you do a lot of short trips? You have to get that out and beat the snot out of it "really". It's a HiPerformance car drive it like