Car wont stay running (data logs attached)

Sho

Sho

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Soooo.... my car wont stay running.

Idles fine for a while and then eventually, RPM will drop like i flipped the key off, the CEL and Battery light will turn on for a sec, then rpm will shoot back up. Never throws a CEL. All grounds are clean and secure. Crank position wiring in the past has caused similar issue, as the harness was rubbing on the passenger axle and caused a short. But when that happened, it would blow the ENG BAR 1 fuse. I replaced that section of the harness and all was well for a few months. The only thing I can think of is the Crank position sensor is taking a shit, and once the car warms up, is when it acts up. Or my ignition switch is failing.



logs are attached with highlighted sections of what its doing.

Car has 214k miles
Built motor has 52k miles
Clutch has 3k miles

Due to nature of my job, I drive about 1k miles a week, and the car is started and shut down 10-15 times a day, 5 days a week.
 

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The CPS would probably make it stall while driving, not just at idle. I would think a faulty TPS would be similar in that it acts up wile at idle or just driving. The AFR's don't look out of whack to me, so I don't think it's a vac leak either.

You don't get any surging while cruising, do you?
 
mangosmoothie said:
The CPS would probably make it stall while driving, not just at idle. I would think a faulty TPS would be similar in that it acts up wile at idle or just driving. The AFR's don't look out of whack to me, so I don't think it's a vac leak either.

You don't get any surging while cruising, do you?
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On Sunday, I thought I had fixed it. Car idled 20 min without issue. Took it for a drive merged on the highway and it shut off. Same manner as it did in these idle logs. After it shut off on the highway, I couldn't get it running for more than 5 sec at a time. Towed it to my friends shop, took 3 hours for AAA to come get me. By the time we got the car to the shop, it fired right back up, idled a few min and then did this. Gave up, went home. Then last night got it to idle 10-15 min. Then caught the attached logs in the OP shortly after as it started acting up.

I did replace the throttle body last night as a precaution, but ended up with the same issues.
 
Have you checked the injector harness ground to make sure it is secure? I had a similar problem before, except the car would run like shit before dying; can't recall if it threw a CEL or not.
 
Oh, so it is stalling while driving? Not just idling?

That sounds more like CPS since it works when cold, gets hot, acts up. Cools off, works again until hot. It's a bitch to test though.
 
JTaylor said:
Have you checked the injector harness ground to make sure it is secure? I had a similar problem before, except the car would run like shit before dying; can't recall if it threw a CEL or not.
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Yep. Pulled the intake manifold on Sunday and checked the Injector harness. Everything was secure. I've had a connector pop off before, but then the car ran like shit and threw a misfire for the corresponding cylinder. No issues like that this time. As far as grounds, the one that is on the Hpfp cover area is secure and clean. I also cleaned and checked the ground near the starter, the one by the PMM and the one from the negative terminal on the battery to the frame.
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mangosmoothie said:
Oh, so it is stalling while driving? Not just idling?

That sounds more like CPS since it works when cold, gets hot, acts up. Cools off, works again until hot. It's a bitch to test though.
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Correct. Usually can't keep it running long enough to drive it, but Sunday I took it for a spin and it did it while on the highway and shut off. And on Thursday last week, I was driving home from work, it did what it's doing in the logs, but while cruising and then shut off. I sat in a parking lot for 30 min, it fired up and I drove it another 5 miles home and it died again in the same manner (rpm fluctuation and eventually shut off) as I pulled into my driveway
 
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I'd check the MAF. Everything else looks normal but MAFv shoots from 1.08 to 1.25v just before shit goes haywire. Might be a similar issue to what I was experiencing with having to wiggle the connector for it to idle right on my car.
 
Enki said:
I'd check the MAF. Everything else looks normal but MAFv shoots from 1.08 to 1.25v just before shit goes haywire. Might be a similar issue to what I was experiencing with having to wiggle the connector for it to idle right on my car.
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I'll take a look at the wiring going into thr maf connector. Ill try my spare maf tonight as well. Thanks!
 
Update. Changed the maf sensor sunday. Drove it 45 miles home from the shop. Then Monday, I made it about 50 miles before the car shut off on me. After it shut off, it just would crank. I left it on the side of the road for 20 min, got back in and it started up and I drove it another 6 miles home.

Saturday night I had a friend pick the car up and load it on his trailer and tow it back to the shop. I Swapped the crank position sensor, let it idle a while, drove it around the block a few times and drove it home again. So far, 140 miles with a few wot pulls without issue. I did suck it up and finally buy a daily driver though. Driving 1000 miles a week in a 500hp car with 214k miles on the Chassis was getting to be too much of a crap shoot
 
I feel like I need to stock up on MAF and CP sensors.
 
Raider said:
I feel like I need to stock up on MAF and CP sensors.
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I don't think the maf was really the issue. I put the old one back on and it hasn't changed anything. We'll see, though
 
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