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2001 LS1 Stumbles and dies. Ideas?

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Old 10-16-2009, 10:12 PM
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Default 2001 LS1 Stumbles and dies. Ideas?

So my 2001 SS isn't running right. It stumbles and dies, almost as if it isnt getting any fuel...unless I hit WOT at which point it seems to clear up and run fine. The problems seem to happen more often at part throttle.

On the interstate, the car would sputter, the tach would show 0 RPM, and the car will die. Since I was travelling 70 MPH at the time, I put the clutch in and just let it coast for a few seconds... re-engage the clutch and it would start again. However, the tach would stay at 0 for 5 or so seconds, then come back up. There was a code for the cam sensor (according to a friend who ran the codes). I went ahead and swapped the cam sensor, (along with the oil pressure sensor I broke in the process) but the problem remains.

Mods on the car are SLP LTs w/ ORY, (done in late 2001), rear O2 codes deleted, and a lid. The O2 sensor harness touches the right side header (as it has since 2001), and it runs through the SLP fire sleeve. I'm planning on checking the condition of that harness this weekend, but I have no idea if I'm barking up the wrong tree on that. Besides the cam sensor code, there were various O2 codes (insufficient switching) that I have been living with for years.

The onset of this problem was pretty sudden (started last Friday). With the exception of a perpetual O2 related SES light, the car has been pretty much fine for years. Oh, and, if relevant, there is a new battery with freshly cleaned terminals as of a month or two ago in the car. The car has 70K miles and is running on original plugs / wires / O2s.

Any ideas would be greatly appreciated.
Old 10-16-2009, 11:31 PM
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Check to see if the O2 harness is melted, might be the crank position sensor, if the tack is doing funny things. Also a good tune up would be in order... New plugs, wires, fuel filter, ect.
Old 10-18-2009, 05:42 PM
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^It very well could be the o2 sensor harness. At WOT the o2 sensors no longer play a role in a/f monitoring, and since at WOT the problem seems to be alleviated I'd check this potential solution first. Also, I've actually had a header burn through an adjacent o2 sensor wire. Sometimes the simplest solution is the answer (hopefully that's the case).
Old 10-18-2009, 06:14 PM
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Long shot but try swaping the ignition relay.
Old 10-19-2009, 09:57 AM
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What is your fuel pressure?
Old 10-20-2009, 10:40 PM
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I installed the crank sensor, but it didn't fix the problem. The harness leading to the sensor feels brittle and appears to have been affected by the heat from the header. I'd like to run a continuity and resistance check on it, but I don't have wiring diagrams / schematics. It seemed to run better for a while on my test drive, but that might be attributable to the cool weather and the fact that the car has been sitting for a while.

I still have to inspect the wires in that harness next to the header.

I will need to have the fuel pressure checked because I no longer have a gauge.

I swapped out the ignition relay, but no change.
Old 10-20-2009, 10:40 PM
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Double post.
Old 10-20-2009, 11:36 PM
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I've got long tubes in mine, and I didn't realize that the connection on the passenger side pre-cat was hanging far too close to the header. I was throwing a code for insufficient switching, she would lope erratically, and bog down and surge at when accelerating. The connection looked fine on the outside, but wouldn't come apart. I cut it out, direct wired around it, and cracked open the original connection. It was filled with corrosion. Idles like a beast again now. Best five minutes I ever invested.
Old 10-24-2009, 11:09 PM
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Melted harness.




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