1999 Z runs terrible on cold start
#1
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Started as it got cooler in the morning, the colder it is on the cold start the worse it gets. As it warms it gets better, but still runs a little rough.
It is also accompanied by the MIL coming on and setting a P0300 (misfire) while idling cold. Then after driving it will usually set a P0171 and P0174 (lean bank 1 & 2). After the 4 consecutive trip of it running normal after that morning start the MIL clears. This happens everyday.
I thought it originally was a vacuum leak from a hole in the PCV hose but I repaired it, and tested the whole for a vacuum leak by spraying with brake clean. Yesterday I sprayed all around the intake etc while running for a vacuum leak, and did the same this morning when cold but found nothing.
My roommate is suggesting intake gaskets. Is this a common issue with the LS1?
It is also accompanied by the MIL coming on and setting a P0300 (misfire) while idling cold. Then after driving it will usually set a P0171 and P0174 (lean bank 1 & 2). After the 4 consecutive trip of it running normal after that morning start the MIL clears. This happens everyday.
I thought it originally was a vacuum leak from a hole in the PCV hose but I repaired it, and tested the whole for a vacuum leak by spraying with brake clean. Yesterday I sprayed all around the intake etc while running for a vacuum leak, and did the same this morning when cold but found nothing.
My roommate is suggesting intake gaskets. Is this a common issue with the LS1?
#2
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Do yourself a favour put in a good set of plugs. If that helps report back.
I would also consider changing out your front two o2 sensors. I know that might get a little pricey but they could be due as well.
I would also consider changing out your front two o2 sensors. I know that might get a little pricey but they could be due as well.
#3
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Started as it got cooler in the morning, the colder it is on the cold start the worse it gets. As it warms it gets better, but still runs a little rough.
It is also accompanied by the MIL coming on and setting a P0300 (misfire) while idling cold. Then after driving it will usually set a P0171 and P0174 (lean bank 1 & 2). After the 4 consecutive trip of it running normal after that morning start the MIL clears. This happens everyday.
I thought it originally was a vacuum leak from a hole in the PCV hose but I repaired it, and tested the whole for a vacuum leak by spraying with brake clean. Yesterday I sprayed all around the intake etc while running for a vacuum leak, and did the same this morning when cold but found nothing.
My roommate is suggesting intake gaskets. Is this a common issue with the LS1?
It is also accompanied by the MIL coming on and setting a P0300 (misfire) while idling cold. Then after driving it will usually set a P0171 and P0174 (lean bank 1 & 2). After the 4 consecutive trip of it running normal after that morning start the MIL clears. This happens everyday.
I thought it originally was a vacuum leak from a hole in the PCV hose but I repaired it, and tested the whole for a vacuum leak by spraying with brake clean. Yesterday I sprayed all around the intake etc while running for a vacuum leak, and did the same this morning when cold but found nothing.
My roommate is suggesting intake gaskets. Is this a common issue with the LS1?
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Last edited by LS6427; 12-12-2013 at 10:25 PM.
#4
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The plugs and wires are new. TR55IX's and Taylor wires.
I've looked at it on a Tech II, O2S activity looks pretty normal. At that point it's running fairly good though, since I don't have access to it til I get to work. MAF Gps second looks right at idle as well. It's a bit high when it's been sitting a while and I start it, but that's because it's idling a little faster.
So try cleaning the MAF. I know my throttle plate good use a cleaning, but It's not so bad that it should cause it into a super lopey idle and want to stall out after starting.
Sometimes it does that, other times it's idling about 1000 RPM and sounds like it's missing it's *** off till the engine it self warms.
I've looked at it on a Tech II, O2S activity looks pretty normal. At that point it's running fairly good though, since I don't have access to it til I get to work. MAF Gps second looks right at idle as well. It's a bit high when it's been sitting a while and I start it, but that's because it's idling a little faster.
So try cleaning the MAF. I know my throttle plate good use a cleaning, but It's not so bad that it should cause it into a super lopey idle and want to stall out after starting.
Sometimes it does that, other times it's idling about 1000 RPM and sounds like it's missing it's *** off till the engine it self warms.
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Started as it got cooler in the morning, the colder it is on the cold start the worse it gets. As it warms it gets better, but still runs a little rough.
It is also accompanied by the MIL coming on and setting a P0300 (misfire) while idling cold. Then after driving it will usually set a P0171 and P0174 (lean bank 1 & 2). After the 4 consecutive trip of it running normal after that morning start the MIL clears. This happens everyday.
I thought it originally was a vacuum leak from a hole in the PCV hose but I repaired it, and tested the whole for a vacuum leak by spraying with brake clean. Yesterday I sprayed all around the intake etc while running for a vacuum leak, and did the same this morning when cold but found nothing.
My roommate is suggesting intake gaskets. Is this a common issue with the LS1?
It is also accompanied by the MIL coming on and setting a P0300 (misfire) while idling cold. Then after driving it will usually set a P0171 and P0174 (lean bank 1 & 2). After the 4 consecutive trip of it running normal after that morning start the MIL clears. This happens everyday.
I thought it originally was a vacuum leak from a hole in the PCV hose but I repaired it, and tested the whole for a vacuum leak by spraying with brake clean. Yesterday I sprayed all around the intake etc while running for a vacuum leak, and did the same this morning when cold but found nothing.
My roommate is suggesting intake gaskets. Is this a common issue with the LS1?