SES light was FLASHING this morning....
SES light was FLASHING this morning.... (new motor on breakin miles, tune is only at 50% ish complete. no WOT testing yet)
its been doing pretty good. then this morning it was pretty chilly. but she started and didnt die. but when i drove off she started poping. (backfires) but smoothed out. then the SES light started flashing. would go away when i let off for a corner or stop light. but would come back after i applied throttle again. car also seemed to have a "pulsing" to it. kinda like driving a 1 cylinder motorcycle or ATV. you could really feel the motor as apposed to a constant humm.
any ideas?
its been doing pretty good. then this morning it was pretty chilly. but she started and didnt die. but when i drove off she started poping. (backfires) but smoothed out. then the SES light started flashing. would go away when i let off for a corner or stop light. but would come back after i applied throttle again. car also seemed to have a "pulsing" to it. kinda like driving a 1 cylinder motorcycle or ATV. you could really feel the motor as apposed to a constant humm.
any ideas?
Mine kinda did the same thing, started running real rough at idle at a red light and then the SES started to flash. Car had almost no power. Got the car home and found that I had a broken intake valve spring...
My car has been driven for 30-40 minutes before so it was up to temp for awhile.
My car has been driven for 30-40 minutes before so it was up to temp for awhile.
definately sounds like a misfire to me, and one way the PCM notifies you is to flash the MLI (SES) light. If you go rent a code scanner from autozone, it'll probably be PO300 or PO30X where X is the cylinder that is misfiring. It will really help because then you can go and check that cylinder for a fouled plug, cracked wire, look for arching, etc. I've been dealing with a misfire in the LT1 I just bought, and I had the same problem where if you're driving the SES flashes but if you're at a stop light it doesn't blink. That has to do with what the conditions in the motor are to set the code (ie the misfire is detected by the crankshaft speed and at idle maybe you're getting misfires but because you're not dumping fuel into that cylinder or cylinders, the exhaust isn't bad enough to cause catalyst damage, which is really what the FLASHING SES light means.)
This is all covered in the service manual. It could be a ton of things causing it, but I'd definatley check plugs/wires. That's where my problem was and that's what everyone recommends when people post about misfires. The service manual also says that if you have a PO30X code and another accompanying code that you fix the other code first to see if it corrects your misfire.
This is all covered in the service manual. It could be a ton of things causing it, but I'd definatley check plugs/wires. That's where my problem was and that's what everyone recommends when people post about misfires. The service manual also says that if you have a PO30X code and another accompanying code that you fix the other code first to see if it corrects your misfire.
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Don't drive your car again until you get this sorted out. If it is a valve spring you do not want to run it again until it's fixed! Hopefully will be an easy fix like a loose plug wire though.
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