Car randomly falls on it's face while under load!
Car randomly falls on it's face while under load! Been working around with this problem for awhile and starting to think about the coils at this point. Randomly when I accelerate the car will just sputter and loose all power. If I push the clutch in and give it some gas it will normally go back to normal. Sometime's it will still continue to do it. It doesn't seem to matter if it's hot or cold it still does it. I got a friend telling me it could be a major loss in compression so he needs to do a compression test to see. I could maybe see that being the case if it was a constant kind of thing. Since it's very random I'm wondering if it's an ECM or Coil issue. The reason I think about the coils is I went a very long time between plug changes and thinking it may have screwed up the resistance or something. Any advice or should I go the compression test route and pray I don't have a major internal problem. Car runs great when it isn't doing this problem.
TECH Regular
Joined: Apr 2010
Posts: 464
Likes: 1
From: California
Getting ready for a cam swap I had the shop baseline dyno my car.
The same thing is happening to my car from 3800-4k RPM . It makes good power and then it falls flat on its face on all 3 dyno pulls.
Initial hunch I would think it would be the coils. Could also be the mass air flow meter or even a collapsing lifter leading to valve issues.
Run the compression test to make sure
The same thing is happening to my car from 3800-4k RPM . It makes good power and then it falls flat on its face on all 3 dyno pulls.
Initial hunch I would think it would be the coils. Could also be the mass air flow meter or even a collapsing lifter leading to valve issues.
Run the compression test to make sure
I do have a bit of a lifter tap that has been there for about 3 years. It is about time for an oil change I will see what that looks like while i'm under there. I thought about unplugging the MAF sensor and see if it makes a difference. I get no SES lights at all when this is happening.
I do have a bit of a lifter tap that has been there for about 3 years. It is about time for an oil change I will see what that looks like while i'm under there. I thought about unplugging the MAF sensor and see if it makes a difference. I get no SES lights at all when this is happening.
My original PCM never threw codes for bad MAF, TPS or IAC valve. Also, when my Crank Shaft Position sensor was killing my engine while I was dirving down the street.....nothing, no codes. A real pain in the ***. Some PCM's show everything.
I've unplugged my MAF before trying to find a problem, I left it unplugged for like 3 months. Tuners told me that my PCM reverted to a SD mode. The engine ran great, down low, mid and top end. No need for the MAF...and gas mileage was the same. So give that a try.....
Also, scan it for codes. You might not get the SES light, but a code could be there.
I'd be leaning toward a PCM or electrical issue. A mechanical issue seems like it would never go away.....and you say it runs great at times, right?
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Yea it run's great most of the time. I just randomly get stuck with this issue. I need to get the emission test done this week and after it's done I will unplug the MAF. I don't think a MAF would cause something like this as randomly but hey they do weird stuff when they start going out.
Yea it run's great most of the time. I just randomly get stuck with this issue. I need to get the emission test done this week and after it's done I will unplug the MAF. I don't think a MAF would cause something like this as randomly but hey they do weird stuff when they start going out.
A failing Crank Shaft Position sensor will cause your issues too. Its a very random thing when they're failing.
Something as simple as a spark plug wire touching or bouncing up against the manifold piping will too.
Maybe even a cracked ceramic part of a spark plug.
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I just changed the plugs 2 weeks ago and i've very very sure I didn't crack the ceramic on any of them. I replaced the Crankshaft Position Sensor a few years ago but it is much cheaper than coil's for sure. I've never really heard of coil problems before so I am not sure what the failure rate on stock coil's is.
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I just changed the plugs 2 weeks ago and i've very very sure I didn't crack the ceramic on any of them. I replaced the Crankshaft Position Sensor a few years ago but it is much cheaper than coil's for sure. I've never really heard of coil problems before so I am not sure what the failure rate on stock coil's is.
Try the Crank sensor.....it take 5 minutes to replace. You can return it if it doesn't help.
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Verdad Gallardo Now that I think about it I changed the Camshaft sensor several years ago not the crankshaft sensor. I've got 234K miles on the car with most of the sensor's still being stock 
A friend is telling me that since I went a very long time between plug changes it could have screwed up the coils. I'm doubtful of this because according to GM it's designed to go 100K miles between plug changes anyways. Granted I would never attempt that but just saying lol. I think I will try and track down a genuine GM part for the crank sensor instead of some advanced auto crap.
A friend is telling me that since I went a very long time between plug changes it could have screwed up the coils. I'm doubtful of this because according to GM it's designed to go 100K miles between plug changes anyways. Granted I would never attempt that but just saying lol. I think I will try and track down a genuine GM part for the crank sensor instead of some advanced auto crap. 